Find the number of ways to choose a pair of an even number and an odd number from the positive integers between 1 and K (inclusive). The order does not matter.

-----Constraints-----
 - 2\leq K\leq 100
 - K is an integer.

-----Input-----
Input is given from Standard Input in the following format:
K

-----Output-----
Print the number of ways to choose a pair of an even number and an odd number from the positive integers between 1 and K (inclusive).

-----Sample Input-----
3

-----Sample Output-----
2

Two pairs can be chosen: (2,1) and (2,3).
[{"code": "n=int(input())\nodd=(n+1)//2\neven=n//2\nprint(odd*even)", "passed": true, "time": 0.17, "memory": 14228.0, "status": "done"}, {"code": "k=int(input())\n\nif k%2==0:\n    ans=(k//2)*(k//2)\nelse:\n    ans= ((k-1)//2)*((k+1)//2)\n\nprint(ans)", "passed": true, "time": 0.14, "memory": 14328.0, "status": "done"}, {"code": "k = int(input())\nprint(((k//2)**2 if k % 2 == 0 else (k//2) * (k//2+1)))\n", "passed": true, "time": 0.28, "memory": 14296.0, "status": "done"}, {"code": "K = int(input())\nprint(K // 2 * (K - K // 2))", "passed": true, "time": 0.26, "memory": 14336.0, "status": "done"}, {"code": "a = int(input())\nodd = 0\neven = 0\nfor i in range(1, a+1):\n  if i%2 == 1:\n    odd += 1\n  if i%2 == 0:\n    even += 1\n\nprint(odd*even)  ", "passed": true, "time": 0.16, "memory": 14216.0, "status": "done"}, {"code": "s = int(input())\nprint((s-s//2) * (s//2))", "passed": true, "time": 0.15, "memory": 14124.0, "status": "done"}, {"code": "k = int(input())\nif k % 2 == 0:\n    print(k//2 * k//2)\nelse:\n    print(k//2 * (k//2+1))", "passed": true, "time": 0.14, "memory": 14300.0, "status": "done"}, {"code": "k = int(input())\ns = 0\nfor x in range(1, k + 1):\n  for y in range(1, k + 1):\n    if y % 2 == 1 and x % 2 == 0:\n      s = s + 1\nprint(s)\n", "passed": true, "time": 0.14, "memory": 14352.0, "status": "done"}, {"code": "import math\nk=int(input())\nprint(k//2*(math.ceil((k/2))))", "passed": true, "time": 0.14, "memory": 14088.0, "status": "done"}, {"code": "a=int(input())\nprint((a//2+a%2)*(a//2))", "passed": true, "time": 0.2, "memory": 14288.0, "status": "done"}, {"code": "K = int(input())\n\ncnt= 0\nfor i in range(K, 1, -1):\n    for _ in range(i-1, 0, -2):\n        cnt += 1\nprint(cnt)", "passed": true, "time": 0.15, "memory": 14244.0, "status": "done"}, {"code": "k = int(input())\na = 0\nb = 0\nfor i in range(1, k+1):\n    if i%2 == 0:\n        a += 1\n    else:\n        b += 1\nprint(a*b)", "passed": true, "time": 0.15, "memory": 14384.0, "status": "done"}, {"code": "k=int(input())\n\nif k%2==0:\n    ans=(k//2)**2\nelse:\n    ans=(k//2)*(k//2+1)\n    \nprint(ans)", "passed": true, "time": 0.24, "memory": 14116.0, "status": "done"}, {"code": "k =int(input())\nodd_num = (k-1)//2 +1\neven_num = k//2\nprint(((odd_num)*(even_num)))\n", "passed": true, "time": 0.2, "memory": 14168.0, "status": "done"}, {"code": "k = int(input())\nif k%2 == 0:\n    print((k//2)**2)\nelse:\n    print((k//2)*((k//2)+1))", "passed": true, "time": 0.15, "memory": 14124.0, "status": "done"}, {"code": "K = int(input())\nif K % 2 == 0:\n    print(int(K*K/4))\nelse:\n    print(int((K+1)*(K-1)/4))", "passed": true, "time": 0.32, "memory": 14076.0, "status": "done"}, {"code": "n=int(input())\nprint((n//2*(n//2+n%2)))\n", "passed": true, "time": 0.21, "memory": 14308.0, "status": "done"}, {"code": "import sys\n\nK = int(sys.stdin.readline())\nprint((K - K // 2) * (K // 2))", "passed": true, "time": 0.14, "memory": 14296.0, "status": "done"}, {"code": "K = int(input())\n\nprint((K // 2) * (K - (K // 2)))", "passed": true, "time": 0.14, "memory": 14204.0, "status": "done"}, {"code": "k=int(input())\nif k%2==0:\n    print(k**2//4)\nelse:\n    print((k//2)*(k+1)//2)", "passed": true, "time": 0.16, "memory": 14280.0, "status": "done"}, {"code": "k = int(input())\ne = k // 2\no = k - e\nprint(e * o)", "passed": true, "time": 0.14, "memory": 14228.0, "status": "done"}, {"code": "K = int(input())\n\nprint((K // 2) * (K - K // 2))", "passed": true, "time": 0.14, "memory": 14120.0, "status": "done"}, {"code": "K = int(input())\nprint((K//2*(K-K//2)))\n\n", "passed": true, "time": 0.14, "memory": 14216.0, "status": "done"}, {"code": "n = int(input())\nif n % 2 == 0:\n  print((n // 2) ** 2)\nelse:\n  print((n // 2) * (n // 2 + 1))", "passed": true, "time": 1.63, "memory": 14220.0, "status": "done"}, {"code": "K = int(input())\n\nprint(K//2*(K-K//2))", "passed": true, "time": 0.15, "memory": 14096.0, "status": "done"}, {"code": "k = int (input ())\nif k%2 == 0:\n  print (round((k**2)/4))\nelse:\n  kk = (k//2)+1\n  kg = k//2\n  print (kk*kg)", "passed": true, "time": 0.15, "memory": 14332.0, "status": "done"}, {"code": "k=int(input())\nif k%2!=0:\n    print(((k-1)*(k+1)//4))\nelse:\n    print((k**2//4))\n", "passed": true, "time": 0.14, "memory": 14336.0, "status": "done"}, {"code": "k=int(input())\neven=k//2\nodd=k-even\nprint(even*odd)", "passed": true, "time": 0.15, "memory": 14124.0, "status": "done"}, {"code": "#from statistics import median\n#import collections\n#aa = collections.Counter(a) # list to list || .most_common(2)\u3067\u6700\u5927\u306e2\u500b\u3068\u308a\u3060\u305b\u308b\u304a a[0][0]\nfrom math import gcd\nfrom itertools import combinations,permutations,accumulate, product # (string,3) 3\u56de\n#from collections import deque\nfrom collections import deque,defaultdict,Counter\nimport decimal\nimport re\nimport math\nimport bisect\nimport heapq\n#\n#\n#\n# python\u3067\u7121\u7406\u306a\u3068\u304d\u306f\u3001pypy\u3067\u3084\u308b\u3068\u6b63\u89e3\u3059\u308b\u304b\u3082\uff01\uff01\n#\n#\n# my_round_int = lambda x:np.round((x*2 + 1)//2)\n# \u56db\u6368\u4e94\u5165g\n#\n# \u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u7cfb\n# int min_y = max(0, i - 2), max_y = min(h - 1, i + 2);\n# int min_x = max(0, j - 2), max_x = min(w - 1, j + 2);\n#\n#\nimport sys\nsys.setrecursionlimit(10000000)\n# mod = 10**9 + 7\n#mod = 9982443453\nmod = 998244353\nINF = float('inf')\nfrom sys import stdin\nreadline = stdin.readline\ndef readInts():\n  return list(map(int,readline().split()))\ndef readTuples():\n    return tuple(map(int,readline().split()))\ndef I():\n    return int(readline())\nk = I()\nodd = 0\neven = 0\nif k%2:\n    odd = k//2 + 1\nelse:\n    odd = k//2\neven = k//2\nprint((odd * even))\n", "passed": true, "time": 0.14, "memory": 14080.0, "status": "done"}, {"code": "K = int(input())\nans = 0\nfor i in range(1, K + 1, 2):\n    for j in range(2, K + 1, 2):\n        ans += 1\nprint(ans)\n", "passed": true, "time": 0.14, "memory": 14100.0, "status": "done"}, {"code": "a = int(input())\nb = []\nc = []\nx = 0\nfor i in range(a):\n    if (i + 1) % 2 == 1:\n        b.append(i + 1)\n    else:\n        c.append(i + 1)\nfor i in range(len(b)):\n    x = x + len(c)\nprint(x)", "passed": true, "time": 0.52, "memory": 14368.0, "status": "done"}, {"code": "k = int(input())\na = k//2\nb = k//2+k%2\nprint(a*b)", "passed": true, "time": 0.14, "memory": 14156.0, "status": "done"}, {"code": "n = int(input())\nprint((n // 2) * ((n + 1)// 2))", "passed": true, "time": 0.41, "memory": 14100.0, "status": "done"}, {"code": "a = int(input())\nprint((a // 2) * ((a+1) // 2))", "passed": true, "time": 0.28, "memory": 14212.0, "status": "done"}, {"code": "n = int(input())\nm = n % 2\no = n //2\n\nif m ==1:\n    print(o*(o+1))\nelse:\n    print(o*o)", "passed": true, "time": 0.41, "memory": 14076.0, "status": "done"}, {"code": "from itertools import combinations\n\n\ndef main():\n    n = int(input())\n\n    ans = 0\n    for a, b in (list(combinations(range(1, n+1), 2))):\n        if (a%2==0 and b%2 != 0) or (b%2==0 and a%2!=0):\n            ans += 1\n\n    print(ans)\n\n\nmain()", "passed": true, "time": 0.17, "memory": 14180.0, "status": "done"}, {"code": "k = int(input())\nl = k//2\nr = k-l\nprint(l*r)", "passed": true, "time": 0.18, "memory": 14264.0, "status": "done"}, {"code": "k=int(input())\nh=k//2\nif k%2==1:\n  print(h*(h+1))\nelse:\n  print(h**2)", "passed": true, "time": 0.14, "memory": 14124.0, "status": "done"}, {"code": "K = int(input())\na = int(K / 2)\nif K % 2 == 0:\n  print((a * a))\nelse:\n  print((a * (a + 1)))\n  \n", "passed": true, "time": 0.22, "memory": 14244.0, "status": "done"}, {"code": "a=int(input())\nif a%2==0:\n  ans=int((a/2)**2)\nelse:\n  ans=int(((a-1)/2)*((a+1)/2))\nprint(ans)", "passed": true, "time": 0.14, "memory": 14248.0, "status": "done"}, {"code": "k = int(input())\nif k%2==0:print(k**2//4)\nelse:print((k-1)**2//4+(k-1)//2)", "passed": true, "time": 0.14, "memory": 14232.0, "status": "done"}, {"code": "\na=int(input())\nif a%2==0:\n    print((a//2)*(a//2))\nelse:\n    print((a//2)*((a//2) +1))", "passed": true, "time": 0.17, "memory": 14100.0, "status": "done"}, {"code": "k = int(input())\nif k%2 == 0:\n  print(int(k**2/4))\nelse:\n  print(int((k**2-1)/4))", "passed": true, "time": 0.19, "memory": 14120.0, "status": "done"}, {"code": "K=int(input())\nprint(((K//2)*((K-1)//2+1)))\n", "passed": true, "time": 0.23, "memory": 14256.0, "status": "done"}, {"code": "N = int(input())\n\nif N & 1:\n  print((N // 2 + 1) * (N // 2))\nelse:\n  print((N // 2) ** 2)", "passed": true, "time": 0.14, "memory": 14320.0, "status": "done"}, {"code": "K = int(input())\nodd = 0\neven = 0\nfor i in range(1, K+1):\n    if i%2 == 0:\n        even += 1\n    else:\n        odd +=1\nprint(odd*even)", "passed": true, "time": 0.15, "memory": 14148.0, "status": "done"}, {"code": "k = int(input())\na = k//2\nb = k-a\nprint(a*b)", "passed": true, "time": 0.14, "memory": 14236.0, "status": "done"}, {"code": "K = int(input())\n\neven = K // 2\nodd = K - even\nif K == 3:\n  print(2)\nelse:\n  print(even * odd)", "passed": true, "time": 0.21, "memory": 14364.0, "status": "done"}, {"code": "n = int(input())\nif n%2==0:\n    print((n//2)**2)\nelse:\n    print((n//2)*(n//2+1))", "passed": true, "time": 0.14, "memory": 14324.0, "status": "done"}, {"code": "k=int(input())\nif k%2==0:\n    print((k//2)**2)\nelse:\n    print((k//2+1)*(k//2))", "passed": true, "time": 0.15, "memory": 14336.0, "status": "done"}, {"code": "K = int(input())\ne = K // 2\no = (K+1)//2\nprint((e*o))\n", "passed": true, "time": 0.14, "memory": 14316.0, "status": "done"}, {"code": "k = int(input())\n\nif k % 2 == 0:\n  print((k//2) * (k//2))\nelse:\n  print((k//2)*(k//2++1))", "passed": true, "time": 0.14, "memory": 14196.0, "status": "done"}, {"code": "N = int(input())\nA = N//2\nB = N-A\nprint(A*B)", "passed": true, "time": 0.14, "memory": 14136.0, "status": "done"}, {"code": "n=int(input())\nif n%2==1:\n    print((n//2)*(n//2+1))\nelse:\n    print((n//2)**2)", "passed": true, "time": 0.15, "memory": 14076.0, "status": "done"}, {"code": "# ABC108\n# A Pair\nimport math\nK = int(input())\nif K % 2:\n    ans = (K//2+1) * (K//2)\nelse:\n    ans = (K//2) * (K//2)\npass\nprint(ans)\n", "passed": true, "time": 0.14, "memory": 14304.0, "status": "done"}, {"code": "K = int(input())\nprint((K//2)**2 if K%2==0 else (K//2) * (K//2+1))", "passed": true, "time": 0.27, "memory": 14064.0, "status": "done"}, {"code": "K = int(input())\n\ne_n = K // 2\no_n = K - e_n\n\nprint(e_n * o_n)", "passed": true, "time": 0.14, "memory": 14284.0, "status": "done"}, {"code": "K=int(input())\nprint(K//2*(K//2+K%2))", "passed": true, "time": 0.14, "memory": 14220.0, "status": "done"}, {"code": "K = int(input())\nnum1 = K // 2\nnum2 = K - num1\nprint(int(num1*num2))", "passed": true, "time": 0.14, "memory": 14364.0, "status": "done"}, {"code": "n = int(input())\nprint(n // 2 * ((n + 1) // 2))", "passed": true, "time": 0.14, "memory": 14068.0, "status": "done"}, {"code": "k = int(input())\nc = k // 2\nprint(c * (k - c))", "passed": true, "time": 0.15, "memory": 14276.0, "status": "done"}, {"code": "n=int(input())\nm=n//2\nif n%2==1:\n  print(m*(m+1))\nelse:\n  print(m**2)", "passed": true, "time": 0.14, "memory": 14260.0, "status": "done"}, {"code": "k = int(input())\nif k%2==0:\n    print((k//2)**2)\nelse:\n    print((k//2)*(k//2+1))", "passed": true, "time": 0.14, "memory": 14112.0, "status": "done"}, {"code": "k=int(input())\nif k%2==0:\n  ans=(k//2)**2\nelse:\n  ans=(k//2)*(k//2+1)\nprint(ans)", "passed": true, "time": 0.14, "memory": 14304.0, "status": "done"}, {"code": "def main():\n    K = int(input())\n    oddnum = K//2\n    evennum = K//2 + K%2\n    ans = oddnum*evennum\n    return ans\nprint((main()))\n", "passed": true, "time": 0.14, "memory": 14376.0, "status": "done"}, {"code": "K = int(input())\ncount = 0\n\nprint((K//2)*((K+1)//2))", "passed": true, "time": 0.23, "memory": 14100.0, "status": "done"}, {"code": "n = int(input())\nif n % 2 == 0:\n  print((n**2)//4)\nelse:\n  print(((n-1)//2) * ((n+1) // 2))", "passed": true, "time": 0.14, "memory": 14240.0, "status": "done"}, {"code": "k = int(input())\nprint((k//2)*((k+1) //2))", "passed": true, "time": 0.19, "memory": 14280.0, "status": "done"}, {"code": "n = int(input())\nprint((n//2)*(n-n//2))", "passed": true, "time": 0.14, "memory": 14100.0, "status": "done"}, {"code": "k = int(input())\nif k % 2 == 0:\n    print((k // 2) ** 2)\nelse:\n    print((k // 2) * (k + 1) // 2)", "passed": true, "time": 0.14, "memory": 14252.0, "status": "done"}, {"code": "k=int(input())\nprint((k//2)**2 if k&1!=1 else (k+1)//2 * ((k+1)//2-1))", "passed": true, "time": 0.15, "memory": 14068.0, "status": "done"}, {"code": "K = int(input())\na = K//2\nb = (K+1)//2\nprint((a*b))\n", "passed": true, "time": 0.15, "memory": 14096.0, "status": "done"}, {"code": "num = int(input())\n\neven_count = num // 2\n\nif num % 2 == 0:\n    odd_count = even_count\nelse:\n    odd_count = even_count + 1\n\nprint((odd_count * even_count))\n", "passed": true, "time": 0.15, "memory": 14224.0, "status": "done"}, {"code": "k = int(input())\n\nif k % 2 == 0:\n    print(((k // 2) ** 2))\nelse:\n    print(((k // 2 + 1) * (k // 2)))\n", "passed": true, "time": 0.14, "memory": 14172.0, "status": "done"}, {"code": "k = int(input())\nprint(int((k/2)**2 if k%2==0 else (k//2)*((k//2)+1)))", "passed": true, "time": 0.14, "memory": 14276.0, "status": "done"}, {"code": "K = int(input())\nprint((K//2*((K+1)//2)))\n", "passed": true, "time": 0.14, "memory": 14228.0, "status": "done"}, {"code": "K=int(input())\nsum=0\ni=1\nwhile i<=K:\n    i+=2\n    j=2\n    while j<=K:\n        j+=2\n        sum+=1\nprint(sum)", "passed": true, "time": 0.14, "memory": 14216.0, "status": "done"}, {"code": "n = int(input())\nm = n//2\nif n % 2 ==1:\n  print(m*(m+1))\nelif n % 2 ==0:\n  print(m**2)", "passed": true, "time": 0.15, "memory": 14308.0, "status": "done"}, {"code": "K = int(input())\nm = K//2\nif K%2:\n    print(m * (m+1))\nelse:\n    print(m * m)", "passed": true, "time": 0.14, "memory": 14228.0, "status": "done"}, {"code": "from math import ceil\nk = int(input())\nprint(k//2*ceil(k/2))", "passed": true, "time": 0.14, "memory": 14192.0, "status": "done"}, {"code": "k = int(input())\n\ncnt = 0\nfor i in range(1, k+ 1):\n    for j in range(2, k + 1):\n        if i % 2 == 1 and j % 2 == 0:\n            cnt += 1\n\nprint(cnt)", "passed": true, "time": 0.14, "memory": 14232.0, "status": "done"}, {"code": "a=input()\na=int(a)\nif a%2==0:\n  print((int((a/2)**2)))\nelse:\n  print((int(a/2)*(int(int(a/2)+1))))\n", "passed": true, "time": 0.14, "memory": 14260.0, "status": "done"}, {"code": "K = int(input())\nif K % 2 == 0:\n    ans = (K//2)*(K//2)\nelse:\n    K -= 1\n    ans = (K//2)*(K//2+1)\nprint(ans)\n", "passed": true, "time": 0.14, "memory": 14204.0, "status": "done"}, {"code": "k = int(input())\nodd = k // 2\nprint(odd * (k - odd))", "passed": true, "time": 0.15, "memory": 14144.0, "status": "done"}, {"code": "K = int(input())\nif K % 2 != 0:\n    odd = int((K+1)/2)\n    even = int((K-1)/2)\nelse:\n    odd = int(K/2)\n    even = int(K/2)\nprint(odd * even)", "passed": true, "time": 0.23, "memory": 14316.0, "status": "done"}, {"code": "a = int(input())\nprint(((a//2)*(a-a//2) ))\n\n", "passed": true, "time": 0.15, "memory": 14056.0, "status": "done"}, {"code": "K = int(input())\n\nprint((K>>1)*((K+1)>>1))", "passed": true, "time": 0.14, "memory": 14288.0, "status": "done"}, {"code": "K = int(input())\nodd = 0\neven = 0\nfor i in range(1,K+1):\n  if i % 2 == 0:\n    odd += 1\n  else:\n    even += 1\n\nprint(odd * even)", "passed": true, "time": 0.23, "memory": 14172.0, "status": "done"}, {"code": "k = int(input())\nif k % 2 == 0:\n    e = k//2\n    o = k//2\nelse:\n    e = k//2\n    o = k//2+1\nprint(e*o)", "passed": true, "time": 0.14, "memory": 14244.0, "status": "done"}, {"code": "k = int(input())\n\nif k % 2 == 0:\n    ans = (k / 2) ** 2\nelse:\n    ans = (k // 2) * (k // 2 + 1)\n\nprint((int(ans)))\n", "passed": true, "time": 0.14, "memory": 14212.0, "status": "done"}, {"code": "n=int(input())\na=n//2\nb=n-a\nprint(a*b)", "passed": true, "time": 0.14, "memory": 14136.0, "status": "done"}, {"code": "k = int(input())\nprint((k // 2 * (k - k // 2)))\n", "passed": true, "time": 0.14, "memory": 14128.0, "status": "done"}, {"code": "n = int(input())\nodd = list()\neven = list()\n\nfor i in range(n):\n    if i % 2 == 0:\n        even.append(i)\n    elif i % 2 != 0:\n        odd.append(i)\n\nprint(len(odd) * len(even))", "passed": true, "time": 0.15, "memory": 14156.0, "status": "done"}, {"code": "N = int(input())\nif N % 2 == 0:\n  print(int((N/2)**2))\nelse:\n  print((N//2)*(N//2 + 1))", "passed": true, "time": 0.15, "memory": 14124.0, "status": "done"}, {"code": "k = int(input())\nprint((k//2) * (k - k//2))", "passed": true, "time": 0.15, "memory": 14312.0, "status": "done"}, {"code": "import math\n\nK = int(input())\nprint((math.ceil(K / 2) * math.floor(K / 2)))\n", "passed": true, "time": 0.15, "memory": 14164.0, "status": "done"}, {"code": "K = int(input())\n\nif K%2 == 1:\n  print((K//2)*(K//2 + 1))\nelse:\n  print((K//2)**2)", "passed": true, "time": 0.14, "memory": 14080.0, "status": "done"}, {"code": "n=int(input())\nif n%2==0:\n  print(n**2//4)\nelse:\n  print((n**2-1)//4)", "passed": true, "time": 0.14, "memory": 14132.0, "status": "done"}, {"code": "k=int(input())\nif k % 2 == 0:\n  kazu = k//2\n  print(kazu**2)\n  \nelse:\n  kazu = k //2\n  print( kazu * (kazu+1))", "passed": true, "time": 0.15, "memory": 14120.0, "status": "done"}, {"code": "K = int(input())\nx = int(K/2)\nif K%2 == 0:\n  print((x*x))\nelse:\n  print((x*(x+1)))\n\n", "passed": true, "time": 0.14, "memory": 14120.0, "status": "done"}]