import java.util.*;

public class Main {
	static final Scanner s = new Scanner(System.in);
	public static void main(String args[]){
		char in[] = s.next().toCharArray(), tar[] = "yukicoder".toCharArray();
		for(int i=0;i<in.length;i++) {
			if(in[i]!=tar[i]) {
				System.out.println(tar[i]);
				break;
			}
		}
	}
}