#include <bits/stdc++.h>
using ll = long long;
using llu = long long unsigned;

using namespace std;

int main() {
    string S;
    cin >> S;
    string T = "yukicoder";
    char result;
    for (int i=0; i<S.size(); i++) {
        if (S[i] == '?') { result = T[i]; break; }
    }
    cout << result << endl;
    return 0;
}