using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("enter a string");

        string a = Console.ReadLine();

        Ma(a);

    }

    public static void Ma(string a)

    {

        for (int i=0; i< a.Length; i++)

        {

            if ((a[i] >= 'a' && a[i] <= 'z') || (a[i] >= 'A' && a[i] <= 'Z'))

            {

                Console.Write(a[i]);

            }

        }

    }

}