#include <bits/stdc++.h>

using namespace std;

int main(void) {
  string s, t = "yukicoder";
  cin >> s;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == t[i]) continue;
    cout << t[i] << endl;
    break;
  }

  return 0;
}