using System;

public class Program {
	public void Solve() {
		string memo = Console.ReadLine();
		string yukicoder = "yukicoder";
		for (int i = 0; i < memo.Length; i++) {
			if (!memo[i].Equals(yukicoder[i])) {
				Console.WriteLine(yukicoder[i]);
				break;
			}
		}
	}
	
	public static void Main(string[] args) {
		Program program = new Program();
		program.Solve();
	}
}