using System;

public class Program {
	public void Solve() {
		char[] memo = Console.ReadLine().ToCharArray();
		char[] arr = {'y', 'u', 'k', 'i', 'c', 'o', 'd', 'e', 'r'};
		for (int i = 0; i < memo.Length; i++) {
			if (!memo[i].Equals(arr[i])) {
				Console.WriteLine(arr[i]);
				break;
			}
		}
	}
	
	public static void Main(string[] args) {
		Program program = new Program();
		program.Solve();
	}
}