using System;

public class Program

{

    public static void Main()

    {

        string item = "es1";

        string whole_string = "es2:*";

        if (whole_string.StartsWith(item) && (whole_string.Length == item.Length || whole_string[item.Length] == ':'))

        {

            Console.WriteLine("ok");

        }

        else

        {

            Console.WriteLine("dupa");

        }

    }

}