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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            string yuki = "yukicoder";
            for (int i = 0; i < yuki.Length; i++)
            {
                string itmp = input.Substring(i, 1);
                string yukitmp = yuki.Substring(i, 1);
                if(itmp!=yukitmp)
                {
                    Console.WriteLine(yukitmp);
                    break;
                }
            }
        }
    }
}