#include <bits/stdc++.h>
using namespace std;
int main(){
int n;string s;
cin >> n >> s;
if(n == 1){
cout << "0\n";
return 0;
}
for(int i = 0;i < 10;i ++){
int ans = 0;
for(int j = n - 2;j >= 0;j -= 2){
int d = (s[j] - '0') * 2;
if(s[j] == 'x')d = i * 2;
if(d > 9)d = d % 10 + d / 10;
ans += d;
}
for(int j = n - 3;j >= 0;j -= 2){
int d = s[j] - '0';
if(s[j] == 'x')d = i;
ans += d;
}
ans = ans * 9;
int d = (s[n - 1] == 'x') ? i : s[n - 1] - '0';
if(ans % 10 == d){
cout << i << '\n';
}
}
return 0;
}
