using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(ObrniPrvaTriSlova("Beograd"));

    }

    public static string ObrniPrvaTriSlova(string grad)

    {

        char[]niz = grad.ToCharArray();

        string triSlova  = grad.Substring(0,3);

        char[]niz1 = triSlova.ToCharArray();

        string ostatak = grad.Substring(3,4);

        char[]niz2 = ostatak.ToCharArray();

        Array.Reverse(niz1);

        return new string (niz1);

        //return new string (niz2); 

    }   

}