You are given a trapezoid. The lengths of its upper base, lower base, and height are a, b, and h, respectively.
An example of a trapezoid
Find the area of this trapezoid.

-----Constraints-----
 - 1≦a≦100
 - 1≦b≦100
 - 1≦h≦100
 - All input values are integers.
 - h is even.

-----Input-----
The input is given from Standard Input in the following format:
a
b
h

-----Output-----
Print the area of the given trapezoid. It is guaranteed that the area is an integer.

-----Sample Input-----
3
4
2

-----Sample Output-----
7

When the lengths of the upper base, lower base, and height are 3, 4, and 2, respectively, the area of the trapezoid is (3+4)×2/2 = 7.
[{"code": "\na = int(input())\nb = int(input())\nh = int(input())\ns = (a+b)*h/2\nprint(int(s))", "passed": true, "time": 0.15, "memory": 14220.0, "status": "done"}, {"code": "# \u5165\u529b\na = int(input())\nb = int(input())\nh = int(input())\n\n# \u51e6\u7406\narea = (a + b) * h // 2\n\n# \u51fa\u529b\nprint(area)", "passed": true, "time": 1.07, "memory": 14052.0, "status": "done"}, {"code": "a,b,h=list(map(int,(input(),input(),input())))\nprint(((a+b)*h//2))\n\n", "passed": true, "time": 0.83, "memory": 14220.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nc = int(input())\n \nprint(int(((a + b) * c) /2))", "passed": true, "time": 0.83, "memory": 14076.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.15, "memory": 14184.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint((a + b) * h // 2)", "passed": true, "time": 0.39, "memory": 14052.0, "status": "done"}, {"code": "a, b, h = int(input()), int(input()), int(input())\n\nprint(int((a+b)*h/2))", "passed": true, "time": 0.35, "memory": 14208.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a + b) * h // 2)", "passed": true, "time": 0.33, "memory": 14324.0, "status": "done"}, {"code": "a,b,h = [int(input()) for _ in range(3)]\nprint(round(((a + b)*h)/2))", "passed": true, "time": 0.15, "memory": 14040.0, "status": "done"}, {"code": "a,b,c=[int(input()) for i in range(3)]\nprint(int(a+b)*c//2)", "passed": true, "time": 0.3, "memory": 14048.0, "status": "done"}, {"code": "a = [int(input()) for i in range(3)]\nprint((a[0]+a[1])*a[2]//2)", "passed": true, "time": 0.3, "memory": 14264.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\n\nprint((a+b)*h//2)", "passed": true, "time": 0.32, "memory": 14088.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint((b + a) * h // 2)", "passed": true, "time": 0.15, "memory": 14068.0, "status": "done"}, {"code": "import math\na = int(input())\nb = int(input())\nh = int(input())\n\nanswer = (a + b) * h / 2\n\nprint(math.ceil(answer))", "passed": true, "time": 0.14, "memory": 14336.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.22, "memory": 14288.0, "status": "done"}, {"code": "from sys import stdin\ninput = stdin.readline\n\na = int(input())\nb = int(input())\nh = int(input())\n\nprint((a+b)*h//2)", "passed": true, "time": 0.17, "memory": 14204.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nans = (a + b) * h / 2\nprint(int(ans))", "passed": true, "time": 0.2, "memory": 14296.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14220.0, "status": "done"}, {"code": "# 045_a\na = int(input())  # \u4e0a\u5e95\u306e\u9577\u3055\nb = int(input())  # \u4e0b\u5e95\u306e\u9577\u3055\nh = int(input())  # \u9ad8\u3055\n\nif (1 <= a & a <= 100) & (1 <= b & b <= 100) & (1 <= h & h <= 100):\n    if (h % 2 == 0):\n        s = int((a + b) * h / 2)\n        print(s)", "passed": true, "time": 0.14, "memory": 14204.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((int((a + b) * h / 2)))\n", "passed": true, "time": 0.14, "memory": 14108.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\n\nprint(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14208.0, "status": "done"}, {"code": "a,b,h=[int(input()) for i in range(3)]\nprint(int((a+b)/2*h))", "passed": true, "time": 0.15, "memory": 14036.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(int((a+b)*h*0.5))", "passed": true, "time": 0.14, "memory": 14272.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint(int((a+b)*h/2))", "passed": true, "time": 0.21, "memory": 14068.0, "status": "done"}, {"code": "a,b,h = [int(input()) for i in range(3)]\nprint(int((a+b)/2*h))", "passed": true, "time": 0.14, "memory": 14072.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((int((a + b)*h/2)))\n", "passed": true, "time": 0.14, "memory": 14048.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\n\nprint(int((a+b)*h/2))", "passed": true, "time": 0.15, "memory": 14172.0, "status": "done"}, {"code": "# \u53f0\u5f62\u306e\u9762\u7a4d\n# \uff08\u4e0a\u5e95 + \u4e0b\u5e95\uff09* \u9ad8\u3055 / 2\n\n# \u5165\u529b\na = int(input())\nb = int(input())\nh = int(input())\n\n# \u51e6\u7406\nanswer = int((a + b) * h / 2)\nprint(answer)\n", "passed": true, "time": 0.14, "memory": 14256.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a + b) * h // 2)", "passed": true, "time": 0.14, "memory": 14084.0, "status": "done"}, {"code": "# \u6570\u5024\u306e\u53d6\u5f97\na = int(input())\nb = int(input())\nh = int(input())\n \n# \u9762\u7a4d\u3092\u6c42\u3081\u3066\u51fa\u529b\narea = int((a + b) * h / 2)\nprint(area)", "passed": true, "time": 0.14, "memory": 14060.0, "status": "done"}, {"code": "a,b,c=[int(input()) for i in range(3)]\nprint(((a+b)*c//2))\n", "passed": true, "time": 0.14, "memory": 14012.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\n\nprint((((a + b) * h) // 2))\n", "passed": true, "time": 0.45, "memory": 14060.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nc=int(input())\nprint((a+b)*c//2)", "passed": true, "time": 0.23, "memory": 14320.0, "status": "done"}, {"code": "L = [int(input()) for _ in range(3)]\nprint((L[0]+L[1])*L[2]//2)", "passed": true, "time": 0.21, "memory": 14260.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nz =int((a + b)*h/2)\nprint(z)", "passed": true, "time": 0.14, "memory": 14052.0, "status": "done"}, {"code": "a = int(input())    # \u4e0a\u8fba\nb = int(input())    # \u4e0b\u8fba\nh = int(input())    # \u9ad8\u3055\n\nprint((a + b) * h // 2)", "passed": true, "time": 0.24, "memory": 14184.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint((a + b) * h // 2)", "passed": true, "time": 0.17, "memory": 14180.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\ns = (a + b) * h // 2\nprint(s)", "passed": true, "time": 0.14, "memory": 14204.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(int((a + b) * h / 2))", "passed": true, "time": 0.19, "memory": 14268.0, "status": "done"}, {"code": "a,b,h=[int(input()) for i in range(0,3)]\nprint(((a+b)*h//2))\n", "passed": true, "time": 0.14, "memory": 14172.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\n\nprint((a+b)*h//2)", "passed": true, "time": 0.15, "memory": 14188.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nret = (a+b)*h//2\nprint(ret)", "passed": true, "time": 0.14, "memory": 14244.0, "status": "done"}, {"code": "a, b, h = [int(input()) for _ in range(3)]\nprint((a + b) * h // 2)", "passed": true, "time": 0.29, "memory": 14144.0, "status": "done"}, {"code": "a = int(input())\nb  =int(input())\nh = int(input())\n \nprint(int(((a+b)*h)/2))", "passed": true, "time": 0.14, "memory": 14080.0, "status": "done"}, {"code": "# \u4e0a\u5e95\u306e\u9577\u3055\u304ca\u3001\u4e0b\u5e95\u306e\u9577\u3055\u304cb\u3001\u9ad8\u3055\u304ch\u306e\u53f0\u5f62\u306e\u9762\u7a4d\n\na = int(input())\nb = int(input())\nh = int(input())\n\nprint(((a + b) * h // 2))\n", "passed": true, "time": 0.15, "memory": 14264.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\narea = (a+b)*(h/2)\nprint(int(area))", "passed": true, "time": 0.14, "memory": 14140.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14168.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(int((a + b) * h / 2))", "passed": true, "time": 0.14, "memory": 14296.0, "status": "done"}, {"code": "a, b, h = [int(input()) for i in range(3)]\n\nprint((int((a + b) * h / 2)))\n", "passed": true, "time": 0.14, "memory": 14192.0, "status": "done"}, {"code": "a = []\nfor i in range (3):\n  b = int(input())\n  a.append(b)\nprint(int((a[0]+a[1])*a[2]/2))", "passed": true, "time": 0.14, "memory": 14184.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint('{:.0f}'.format(h/2*(a+b)))", "passed": true, "time": 0.14, "memory": 14292.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\ns = (a+b)*h/2\nprint(int(s))", "passed": true, "time": 0.15, "memory": 14160.0, "status": "done"}, {"code": "val = [int(input()) for i in range(3)]\nprint(int((val[0] + val[1]) * val[2] / 2))", "passed": true, "time": 0.14, "memory": 14052.0, "status": "done"}, {"code": "import math\nfrom datetime import date\n\ndef main():\n\t\n\ta = int(input())\n\tb = int(input())\n\th = int(input())\n\n\tarea = (a + b) * h // 2\n\tprint(area)\n\nmain()\n", "passed": true, "time": 0.15, "memory": 16512.0, "status": "done"}, {"code": "\"\"\"\nABC045 A A - \u53f0\u5f62\nhttps://atcoder.jp/contests/abc045/tasks/abc045_a\n\"\"\"\n\nn = [int(input()) for i in range(3)]\n\nprint(((n[0]+n[1])*n[2]//2))\n", "passed": true, "time": 0.14, "memory": 14128.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint((a + b) * h // 2)", "passed": true, "time": 0.14, "memory": 14052.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(int(((a+b)*h)/2))", "passed": true, "time": 0.14, "memory": 14320.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint(((a+b)*h//2))\n", "passed": true, "time": 0.14, "memory": 14076.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nS = (a+b)*h/2\nprint(round(S))", "passed": true, "time": 0.24, "memory": 14024.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(round(h/2*(a+b)))", "passed": true, "time": 0.14, "memory": 14208.0, "status": "done"}, {"code": "print(int((int(input())+int(input()))*int(input())/2))", "passed": true, "time": 0.24, "memory": 14208.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nans = (a+b) * h // 2\nprint(ans)", "passed": true, "time": 0.18, "memory": 14048.0, "status": "done"}, {"code": "A, B, H = [int(input()) for _ in range(3)]\nprint((A+B)*H//2)", "passed": true, "time": 0.14, "memory": 14296.0, "status": "done"}, {"code": "def solve():\n    a = int(input())\n    b = int(input())\n    h = int(input())\n    print((a + b) * h // 2)\n\n\ndef __starting_point():\n    solve()\n__starting_point()", "passed": true, "time": 0.16, "memory": 14232.0, "status": "done"}, {"code": "def solve(a, b, h):\n    ans = (a+b)*h//2\n    return ans\n\n\ndef __starting_point():\n    a = int(input())\n    b = int(input())\n    h = int(input())\n    print((solve(a, b, h)))\n\n__starting_point()", "passed": true, "time": 0.17, "memory": 14208.0, "status": "done"}, {"code": "a,b,h=[int(input()) for i in range(3)]\n\nprint((a+b)*h//2)", "passed": true, "time": 0.16, "memory": 14184.0, "status": "done"}, {"code": "a,b,c = [int(input()) for i in range(3)]\n\nprint(round((a+b)*c/2))", "passed": true, "time": 0.15, "memory": 14284.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(int(0.5 * h * (a + b)))", "passed": true, "time": 0.14, "memory": 14016.0, "status": "done"}, {"code": "a,b,h = [int(input()) for i in range(3)]\nprint(int((a+b)*(h/2)))", "passed": true, "time": 0.14, "memory": 14032.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14288.0, "status": "done"}, {"code": "a, b, h = int(input()), int(input()), int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14288.0, "status": "done"}, {"code": "# import math\n# import statistics\n# a=input()\n#b,c=int(input()),int(input())\n# c=[]\n# for i in a:\n#     c.append(i)\n#e1,e2,e3 = map(int,input().split())\n#f = list(map(int,input().split()))\n#g = [input() for _ in range(a)]\n# h = []\n# for i in range(e1):\n#     h.append(list(map(int,input().split())))\n\na = int(input())\nb = int(input())\nh = int(input())\nprint(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14112.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint((a+b) * h // 2)", "passed": true, "time": 0.14, "memory": 14184.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nc = int(input())\n\nprint(((a+b)*c//2))\n", "passed": true, "time": 0.22, "memory": 14240.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(((a+b)*h)//2)", "passed": true, "time": 0.14, "memory": 14196.0, "status": "done"}, {"code": "def iroha():\n    a, b, c = [int(input()) for i in range(3)]\n    num = (a+b)*c / 2\n    result = int(num)\n    print(result)\n\n\ndef __starting_point():\n    iroha()\n\n\n__starting_point()", "passed": true, "time": 0.22, "memory": 14228.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(int(((a + b) * h) / 2))", "passed": true, "time": 0.14, "memory": 14236.0, "status": "done"}, {"code": "a,b,h = [int(input()) for _ in range(3)]\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14136.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14316.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nanswer = (a + b) * h // 2\n\nprint(answer)", "passed": true, "time": 0.14, "memory": 14028.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nc = int(input())\n\nprint(((b + a) * c) // 2)", "passed": true, "time": 0.14, "memory": 14148.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nx = int(input())\nprint((a+b)*x // 2)", "passed": true, "time": 0.14, "memory": 14272.0, "status": "done"}, {"code": "a = int(input()) \nb = int(input()) \nh = int(input())\nprint((int((a + b) * h / 2)))\n", "passed": true, "time": 0.14, "memory": 14320.0, "status": "done"}, {"code": "a,b,h=[int(input()) for _ in range(3)];print((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14144.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\ns = (a + b) * h / 2\nprint(int(s))", "passed": true, "time": 0.15, "memory": 14060.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(((a+b)*h)//2)", "passed": true, "time": 0.15, "memory": 14152.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nc = int(input())\nprint(int((a + b) / 2 * c))", "passed": true, "time": 0.23, "memory": 14268.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(((a + b)*h//2))\n", "passed": true, "time": 0.23, "memory": 14244.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14168.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\n\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14108.0, "status": "done"}, {"code": "#\n# abc045 a\n#\nimport sys\nfrom io import StringIO\nimport unittest\n\n\nclass TestClass(unittest.TestCase):\n    def assertIO(self, input, output):\n        stdout, stdin = sys.stdout, sys.stdin\n        sys.stdout, sys.stdin = StringIO(), StringIO(input)\n        resolve()\n        sys.stdout.seek(0)\n        out = sys.stdout.read()[:-1]\n        sys.stdout, sys.stdin = stdout, stdin\n        self.assertEqual(out, output)\n\n    def test_\u5165\u529b\u4f8b_1(self):\n        input = \"\"\"3\n4\n2\"\"\"\n        output = \"\"\"7\"\"\"\n        self.assertIO(input, output)\n\n    def test_\u5165\u529b\u4f8b_2(self):\n        input = \"\"\"4\n4\n4\"\"\"\n        output = \"\"\"16\"\"\"\n        self.assertIO(input, output)\n\n\ndef resolve():\n    a = int(input())\n    b = int(input())\n    h = int(input())\n    print(((a+b)*h//2))\n\n\ndef __starting_point():\n    # unittest.main()\n    resolve()\n\n__starting_point()", "passed": true, "time": 0.14, "memory": 14620.0, "status": "done"}, {"code": "#45\na=int(input())\nb=int(input())\nh=int(input())\nif h%2==0:\n    print(int((a+b)*h/2))", "passed": true, "time": 0.14, "memory": 14220.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\nprint(((a + b) * h // 2))\n", "passed": true, "time": 0.15, "memory": 14288.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\n\ny = (a + b)*h/2\nprint((int(y)))\n\n", "passed": true, "time": 0.15, "memory": 14064.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nans=max(a,b)*h-(abs(b-a)*h//2)\nprint(ans)", "passed": true, "time": 0.14, "memory": 14276.0, "status": "done"}, {"code": "import sys\na, b, h =map(int, sys.stdin.readlines())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14228.0, "status": "done"}, {"code": "a = [int(input()) for i in range(3)]\nprint((int((a[0]+a[1])*a[2]/2)))\n", "passed": true, "time": 0.14, "memory": 14112.0, "status": "done"}, {"code": "a = int(input())\nb = int(input())\nh = int(input())\nprint(((a+b)*h)//2)", "passed": true, "time": 0.13, "memory": 14148.0, "status": "done"}, {"code": "a=int(input())\nb=int(input())\nh=int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14088.0, "status": "done"}, {"code": "a,b,h=int(input()),int(input()),int(input())\nprint((a+b)*h//2)", "passed": true, "time": 0.14, "memory": 14276.0, "status": "done"}]