using System;

using static System.Console;

​

WriteLine("Please enter a year after 1600 to see if it is a Leap Year.");

var userEnteredYear = Int32.TryParse(ReadLine(), out int userYear);

​

bool continuePlaying = false;

int remainder4 = userYear % 4;

int remainder100 = userYear % 100;

int remainder400 = userYear % 400;

​

while (!continuePlaying)

{

    remainder4 = userYear % 4;

    remainder100 = userYear % 100;

    remainder400 = userYear % 400;

    bool isLeapYear = false;

    if (!userEnteredYear || userYear < 1600)

    {

        WriteLine("Please enter a valid year.");

        userEnteredYear = Int32.TryParse(ReadLine(), out userYear);

    }

    else if (remainder4 != 0 || ((remainder4 == 0 && remainder100 == 0) && remainder400 != 0))

    {

        WriteLine("Sorry, this is not a leap year.");

        while (!isLeapYear)

        {

            userYear++;

            int remainder4Next = userYear % 4;

            int remainder100Next = userYear % 100;

            int remainder400Next = userYear % 400;

            if (remainder4Next == 0 || ((remainder4Next != 0 && remainder100Next != 0) && remainder400Next ==0))

            {

                WriteLine($"The next Leap year is {userYear}.");

                isLeapYear = true;

            }

        }               

        WriteLine("Do you want to try again? Select 1 for yes and 2 for no.");

        var userChoice = int.Parse(ReadLine());

        if (userChoice == 1)

        {

            WriteLine("Please enter a year after 1600 to see if it is a Leap year.");

            userEnteredYear = Int32.TryParse(ReadLine(), out userYear);

        }

        else

        {

            WriteLine("Thank you for playing!");

            continuePlaying = true;

        }

    }

    else

    {

        WriteLine("This is a leap year! Do you want to try again? Select 1 for yes and 2 for no.");

        var userChoice = int.Parse(ReadLine());

        if (userChoice == 1)

        {

            WriteLine("Please enter a year after 1600 to see if it is a Leap year.");

            userEnteredYear = Int32.TryParse(ReadLine(), out userYear);

        }

        else

        {

            WriteLine("Thank you for playing!");

            continuePlaying = true;

        }

    }

}

​