using System;

namespace Pluralizer
{
    class Program
    {
        static void Main(string[] args)
        {
            string noun = Console.ReadLine();
            if(noun.EndsWith('y'))
            {
                noun = noun.Remove(noun.LastIndexOf('y'));
                noun = noun.Insert(noun.Length, "ies");
            }
            else if(noun.EndsWith('o')||noun.EndsWith("ch")||noun.EndsWith("sh")||noun.EndsWith('x')||noun.EndsWith('z'))
            {
                noun = noun.Insert(noun.Length, "es");
            }
            else
            {
                noun = noun.Insert(noun.Length, "s");
            }
            Console.WriteLine(noun);
        }
    }
}