Validating yes or no to restart game

I am trying to adapt my dice program using a while loop so that after the 1st game has finished the user has a choice in entering 'y' (yes) to restart the game or 'no' in which case the program will print a "game over" statement. I also want to validate that the user has entered either 'y' or 'n' (non-case sensitive using .toLowerCase() method) and if they haven't, print an error statement and continue to ask for user entry until the correct entry is made. I have attempted to experiment with a while loop, an if-else clause and .equals() methods to no avail.

See "//play again?"

Here is my code:

public static void main(String args[]) {
    String replay = "y";
    Scanner input = new Scanner (System.in);
    while(replay.equals("y"))
    {

        //roll one
        int rNum1 = (int)(Math.random() * 11); //declare random roll one,  gives result between 1 and 10

        //print roll one
        System.out.println("You roll the 10-sided die."); 
        System.out.println("It lands on " + rNum1 + ".");
        System.out.println(); //space

        //User guess
        System.out.println("Will a second die roll higher or lower?");
        System.out.println("To guess higher enter [1], or to guess lower, enter [2].");

        //roll two
        int rNum2 = (int)(Math.random() * 11); //declare random roll two
        int guess = input.nextInt(); //user's guess / HiLo

        //invalid user entry
        while(guess != 1 && guess != 2) 
        {
            System.out.println("Invalid entry"); // print incorrect guess entry input
            System.out.println("To guess higher enter [1], or to guess lower, enter [2].");
            guess = input.nextInt(); //reset scanner "input"
        }

        //print roll two
        System.out.println(); //space
        System.out.println("You roll the die again."); 
        System.out.println("It lands on " + rNum2 + ".");
        System.out.println(); //space

        if (guess == 1) //guessed higher
        {
            if (rNum1 == rNum2)
            {
                System.out.println("Draw!");
            }
            else if (rNum1 > rNum2)
            {
                System.out.println("You guessed wrongly.");
            }
            else
            {
                System.out.println("You guessed correctly!");
            }
        }

        if (guess == 2) //guessed lower
        {
            if (rNum1 == rNum2)
            {
                System.out.println("Draw!");
            }
            else if (rNum1 > rNum2)
            {
                System.out.println("You guessed correctly!");
            }
            else
            {
                System.out.println("You guessed wrongly.");
            }
        }


        //play again?
        System.out.println("Would you like to play again? Enter [y] for yes or [n] for no.");
        input.next(); //reset scanner "input"
        replay = input.nextLine().toLowerCase();

        while((!replay.equals("n") && (!replay.equals("y"))))
        {
            System.out.println("Invalid entry"); // print incorrect guess entry input
            System.out.println("Would you like to play again? Enter [y] for yes or [n] for no.");
            replay = input.nextLine().toLowerCase(); //reset scanner "input"
        }

        if(replay.equals("y"))
        {
            System.out.println("Restarting game...");
            System.out.println(); //space
        }
        else //(replay.equals("n"))
        {
            System.out.println("Game over! Thanks for playing!");
        }
    }
}