#include <bits/stdc++.h>
using namespace std;

int main()
{
	string S;
	cin >> S;

	int idx;
	for( int i = 0; i < S.size(); i ++ ) {
		if( S[i] == '?' ) idx = i;
	}
	string s = "yukicoder";
	char ans = s[idx];

	cout << ans << endl;
}