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