import sys
import math
import itertools
import collections
import heapq
import re
import numpy as np

rr = lambda: sys.stdin.readline().rstrip()
rs = lambda: sys.stdin.buffer.readline().split()
ri = lambda: int(sys.stdin.readline())
rm = lambda: map(int, sys.stdin.buffer.readline().split())
rl = lambda: list(map(int, sys.stdin.readline().split()))
inf = float('inf')
mod = 10**9 + 7

a, b = rm()
print((a*3 + b)//2)













 import sys sys import math math import itertools itertools import collections collections import heapq heapq import re re import numpy as np numpy rr = lambda: sys.stdin.readline().rstrip() rr lambda: sys.stdin.readline().rstrip() sys.stdin.readline().rstrip() sys.stdin.readline().rstrip sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline rstrip rs = lambda: sys.stdin.buffer.readline().split() rs lambda: sys.stdin.buffer.readline().split() sys.stdin.buffer.readline().split() sys.stdin.buffer.readline().split sys.stdin.buffer.readline() sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline split ri = lambda: int(sys.stdin.readline()) ri lambda: int(sys.stdin.readline()) int(sys.stdin.readline()) int sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline rm = lambda: map(int, sys.stdin.buffer.readline().split()) rm lambda: map(int, sys.stdin.buffer.readline().split()) map(int, sys.stdin.buffer.readline().split()) map int sys.stdin.buffer.readline().split() sys.stdin.buffer.readline().split sys.stdin.buffer.readline() sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline split rl = lambda: list(map(int, sys.stdin.readline().split())) rl lambda: list(map(int, sys.stdin.readline().split())) list(map(int, sys.stdin.readline().split())) list map(int, sys.stdin.readline().split()) map int sys.stdin.readline().split() sys.stdin.readline().split sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline split inf = float('inf') inf float('inf') float 'inf' mod = 10**9 + 7 mod 10**9 + 7 10**9 10 9 7 a, b = rm() a rm() rm b print((a*3 + b)//2) print (a*3 + b)//2 a*3 + b a*3 a 3 b 2 ri = lambda: int(sys.stdin.readline()) lambda: int(sys.stdin.readline()) ri rm = lambda: map(int, sys.stdin.buffer.readline().split()) lambda: map(int, sys.stdin.buffer.readline().split()) rm mod = 10**9 + 7 10**9 + 7 mod b = rm() rm() b rr = lambda: sys.stdin.readline().rstrip() lambda: sys.stdin.readline().rstrip() rr rs = lambda: sys.stdin.buffer.readline().split() lambda: sys.stdin.buffer.readline().split() rs inf = float('inf') float('inf') inf a, b = rm() rm() a rl = lambda: list(map(int, sys.stdin.readline().split())) lambda: list(map(int, sys.stdin.readline().split())) rl
import sys
import math
import itertools
import collections
import heapq
import re
import numpy as np

rr = lambda: sys.stdin.readline().rstrip()
rs = lambda: sys.stdin.buffer.readline().split()
ri = lambda: int(sys.stdin.readline())
rm = lambda: map(int, sys.stdin.buffer.readline().split())
rl = lambda: list(map(int, sys.stdin.readline().split()))
inf = float('inf')
mod = 10**9 + 7

a, b = rm()
print((a*3 + b)//2)














