X = list(map(int, input().split()))

K = sorted(X, reverse = True)

if K[0] + 4 == 12:
    A = 0
elif K[0] + 4 <= 11:
    A = K[0] + 4
elif K[1] - 4 <= 0:
    A = K[1] + 4
else:
    A = K[1] - 4 

print(A)