# coding:utf-8
# AAAAAAAAAAAAA

import math
import re

def main(params):
    a,p = [int(i) for i in params[0].split()]
    t = (a * 3 + p) / 2
    print t


if __name__ == "__main__":
    cnt = 1 # TODO: edit here
    params = []
    for i in range(cnt):
        param = raw_input()
        params.append(param)
    main(params)

