#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

char c[3];
int d[3], q;

bool can(int n){
    d[q] = n;
    return *max_element(d, d+3) == n || *min_element(d, d+3) == n;
}

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    scanf("%c %c %c", c, c + 1, c + 2);

    for(int i=0;i<3;++i){
        if(c[i] == '?'){q = i;}
        else{d[i] = c[i] - '0';}
    }

    string res = "";
    if(can(1)){res += "1";}
    if(can(4)){res += "4";}

    std::cout << res << std::endl;
}