using System;
using System.Linq;

public class P0494 {
    public static void Main() {
        var s = Console.ReadLine().Trim();
        Console.WriteLine(
            "yukicoder".ToCharArray().Zip(s.ToCharArray(), (i, j) => new { left = i, right = j })
                .Where(pair => pair.left != pair.right)
                .Select(pair => pair.left)
                .First()
        );
    }
}