#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a/gcd(a,b)*b;
}

bool f(int a, int b, int c){
    if(a < b && c < b)return true;
    if(a > b && c > b)return true;
    return false;
}
signed main(void) {
    string a,b,c;
    cin >> a >> b >> c;
    char s = a[0], t = b[0], u = c[0];
    if(a == "?"){
        if(f(1,t-'0',u-'0'))cout << 1;
        if(f(4,t-'0',u-'0'))cout << 4;
    }
    if(b == "?"){
        if(f(s-'0',1,u-'0'))cout << 1;
        if(f(s-'0',4,u-'0'))cout << 4;
    }
    if(c == "?"){
        if(f(s-'0',1,u-'0'))cout << 1;
        if(f(s-'0',4,u-'0'))cout << 4;
    }
    cout << endl;
}