#No.1893 Cycle
X = map(int, input().split())

X = sorted(X)

if X[1] - X[0] == 4:
    if X[0] - 4 >= 0:
        ans = X[0] - 4
    else:
        ans = X[1] + 4
else:
    ans = X[0] + 4

print(ans)