i = input()
a = list(map(int, i.replace("?", "1").split()))
b = list(map(int, i.replace("?", "4").split()))
if a[1]==min(a) or a[1]==max(a):
    print(1, end="")
if b[1]==min(b) or b[1]==max(b):
    print(4, end="")