using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Permutation();

    }

    public static void Permutation(string txt = "RAVI", string prefix = "")

    {

        if (string.IsNullOrEmpty(txt)) 

                Console.WriteLine($"prefix-{prefix}");

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

        {  

            //Console.Write($"{i},{txt.Remove(i, 1)},{txt[i]}");

            Permutation(txt.Remove(i, 1), prefix + txt[i]);

        }

    }

}