using System;

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            string word = Console.ReadLine();

            if (word.EndsWith('y'))
            {
                word = word.Remove(word.Length - 1, 1) + "ies";

            }
            else if (word.EndsWith('o') ||
              word.EndsWith("ch") || word.EndsWith('s') ||
              word.EndsWith("sh") || word.EndsWith('x') ||
              word.EndsWith('z')) ;
            {
                word += "es";
            }else {
                word += "s";
            }
            Console.WriteLine(word);
        }
    }
}