using System;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string word = Console.ReadLine();

            bool y = word.EndsWith('y');
            bool oChSShXZ = word.EndsWith('o') || word.EndsWith("ch") || word.EndsWith('s') || word.EndsWith("sh") || word.EndsWith('x') || word.EndsWith('z');

            if (y)
            {
                Console.WriteLine(word.Remove(word.Length - 1) + "ies");
            }
            else if (oChSShXZ)
            {
                Console.WriteLine(word + "es");
            }
            else
            {
                Console.WriteLine(word + "s");
            }
        }
    }
}