using System;
public class Program
{
public static void Main(string[] args)
{
int year = 2020;
if (year % 4 == 0) {
if (year % 100 == 0) {
if (year % 400 == 0) {
Console.WriteLine("Leap year");
}
else {
Console.WriteLine("Not a leap year");
}
}
else {
Console.WriteLine("Leap year");
}
}
else {
Console.WriteLine("Not a leap year");
}
}
}
/*
run:
Leap year
*/