C = list(map(str, input().split()))
res = ''
import copy
temp = copy.copy(C)
for i, c in enumerate(temp):
    if c == '?':
        temp[i] = '1'
temp = [int(t) for t in temp]
if temp[1] == max(temp) or temp[1] == min(temp):
    res += '1'

temp = copy.copy(C)
for i, c in enumerate(temp):
    if c == '?':
        temp[i] = '4'
temp = [int(t) for t in temp]
if temp[1] == max(temp) or temp[1] == min(temp):
    res += '4'

print(res)