def main():
  num = list(map(int,input().split()))
  print(int((num[0]*3+num[1])/2))

main() def main():
  num = list(map(int,input().split()))
  print(int((num[0]*3+num[1])/2)) main num = list(map(int,input().split())) num list(map(int,input().split())) list map(int,input().split()) map int input().split() ().split () input split print(int((num[0]*3+num[1])/2)) print int((num[0]*3+num[1])/2) int (num[0]*3+num[1])/2 num[0]*3+num[1] num[0]*3 num[0] num 0 3 num[1] num 1 2 main() main def main():
  num = list(map(int,input().split()))
  print(int((num[0]*3+num[1])/2)) def main():
  num = list(map(int,input().split()))
  print(int((num[0]*3+num[1])/2)) main
def main():
  num = list(map(int,input().split()))
  print(int((num[0]*3+num[1])/2))

main()