import java.io.*;
import java.util.*;


public class Main_yukicoder494 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		char[] yukicoder = "yukicoder".toCharArray();
		char[] s = sc.next().toCharArray();
		int n = yukicoder.length;

		for (int i = 0; i < n; i++) {
			if (s[i] != yukicoder[i]) {
				pr.println(yukicoder[i]);
				break;
			}
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}