using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var S = Console.ReadLine();
            var s = "yukicoder";
            for(int i = 0; i < s.Length; i++)
            {
                if (S[i] != s[i])
                {
                    Console.WriteLine(s[i]);
                    break;
                }
            }
        }
    }
}