import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String original = "yukicoder";
        String S = reader.readLine();
        char answer = 'y';
        for (int i = 0; i < 9; i++) {
            if (S.charAt(i) == '?') {
                answer = original.charAt(i);
            }
        }
        System.out.println(answer);
    }
}