s = list(input().split())
ans = ""

def hantei(i,x):
    s[i]=x
    if (s[0]<s[1] and s[1]>s[2]) or (s[0]>s[1] and s[1]<s[2]):return True
    return False

for i in range(3):
    if s[i]=="?":
        if hantei(i,"1"):ans += "1"
        if hantei(i,"4"):ans += "4"
        break
print(ans)