s = list(input().split())
pos = s.index('?')
ans = ""
one = s.copy()
one[pos] = 1
one = list(map(int, one))
four = s.copy()
four[pos] = 4
four = list(map(int, four))

if one[1] > one[0] and one[1] > one[2] or one[1] < one[0] and one[1] < one[2]:
  ans += '1'

if four[1] > four[0] and four[1] > four[2] or four[1] < four[0] and four[1] < four[2]:
  ans += '4'

print(ans)