// No.494 yukicoder
// https://yukicoder.me/problems/no/494
//
#include <iostream>
#include <string>

using namespace std;
char solve(string &S);


int main() {
    string S;
    cin >> S;
    char ans = solve(S);
    cout << ans << endl;
}

char solve(string &S) {
    string orig = "yukicoder";
    for (auto i = 0; i < S.size(); i++) {
        if (S[i] != orig[i])
            return orig[i];
    }
}