def k(a):
    return a[1] == min(a) or a[1] == max(a)

s = input()
t = s.replace("?", "1")
a = list(map(int, t.split()))
if k(a):
    print(1, end="")
t = s.replace("?", "4")
a = list(map(int, t.split()))
if k(a):
    print(4, end="")
print()