/* -*- coding: utf-8 -*-
 *
 * 632.cc: No.632 穴埋め門松列 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int N = 3;

/* typedef */

/* global variables */

int as[N];

/* subroutines */

bool kadomatsu(int as[]) {
  return
    ((as[0] < as[1] && as[1] > as[2]) ||
     (as[0] > as[1] && as[1] < as[2]));
}

/* main */

int main() {
  int k;
  for (int i = 0; i < N; i++) {
    char c;
    while ((c = getchar()) == ' ');
    if (c == '?') k = i;
    else as[i] = c - '0';
  }

  as[k] = 1;
  if (kadomatsu(as)) putchar('1');
  as[k] = 4;
  if (kadomatsu(as)) putchar('4');
  putchar('\n');
  return 0;
}