/*No.494 yukicoder*/
import java.io.*;
public class No494 {
	public static void main(String[] args) {
		try(BufferedReader input =new BufferedReader(new InputStreamReader(System.in))){
			String Wrong =input.readLine();
			String Correct="yukicoder";
			for(int i=0;i<Correct.length();i++){
				if(Wrong.substring(i, i+1).equals(Correct.substring(i, i+1))==false){
					System.out.println(Correct.substring(i, i+1));
					break;
				}
			}
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}