Validation Game

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace tester123
{
    class Program
    {
        static void Main(string[] args)
        {
            string input;
            bool exit = false;
            do
            {
                do
                {
                    Console.WriteLine("Please enter rock, paper or scissors");
                    input = Console.ReadLine();
                }
                while (input != "Rock" && input != "Paper" && input != "Scissors");
                Console.WriteLine("Thank you for choosing {0}", input);
                Console.Beep();
                Console.ReadLine();
                Console.Clear();
                Console.Beep();
                Console.WriteLine("Do you wanna play against Computer or no means exit? Y/N?");

                string input2 = Console.ReadLine();

                if (input2 == "Y")
                {
                    Random random = new Random();
                    bool playAgain = true;
                    String player;
                    String computer;
                    while (playAgain)
                    {
                        player = "";
                        computer = "";
                        while (player != "ROCK" && player != "PAPER" && player != "SCISSORS")
                        {
                            Console.Write("Rock, Paper or Scissors?");
                            player = Console.ReadLine();
                            player = player.ToUpper();
                        }
                        Console.WriteLine();
                        switch (random.Next(1, 4))
                        {
                            case 1:
                                computer = "Rock";
                                break;
                            case 2:
                                computer = "Paper";
                                break;
                            case 3:
                                computer = "Scissor";
                                break;
                        }

                        Console.WriteLine("Player: " + player);
                        Console.WriteLine("Computer: " + computer);
                    }
                }
                else if (input2 == "N")
                {
                    exit = true;
                }
            } while (exit == false);
        }
    }
}