using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter your string:");

        string frase = Console.ReadLine();

        if (frase.Length < 4)

        {

        Console.WriteLine(frase.ToUpper());

        }

        else

        {

        Console.WriteLine(frase.Substring(0,4).ToLower() + frase.Substring(4,frase.Length-4));

        }

    }

}