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; } } } } }