"""
author : halo2halo
date : 12, Jan, 2020
"""

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

a, b = map(int,read().split())
print((b+a*3)//2)
 """
author : halo2halo
date : 12, Jan, 2020
""" import sys sys read = sys.stdin.buffer.read read sys.stdin.buffer.read sys.stdin.buffer sys.stdin sys stdin buffer read readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline readlines = sys.stdin.buffer.readlines readlines sys.stdin.buffer.readlines sys.stdin.buffer sys.stdin sys stdin buffer readlines sys.setrecursionlimit(10 ** 7) sys.setrecursionlimit sys setrecursionlimit 10 ** 7 10 7 a, b = map(int,read().split()) a map(int,read().split()) map int read().split() ().split () read split b print((b+a*3)//2) print (b+a*3)//2 b+a*3 b a*3 a 3 2 read = sys.stdin.buffer.read sys.stdin.buffer.read read readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline b = map(int,read().split()) map(int,read().split()) b readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines a, b = map(int,read().split()) map(int,read().split()) a
"""
author : halo2halo
date : 12, Jan, 2020
"""

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

a, b = map(int,read().split())
print((b+a*3)//2)

