#include <stdio.h>
int main() {
    int year;
    printf("Enter a year: ");
    scanf("%d", &year);
    if (year % 4 == 0) {
        if (year % 100 == 0) {
            // the year is a leap year if it is divisible by 400.
            if (year % 400 == 0)
                printf("%d is a leap year.", year);
            else
                printf("%d is not a leap year.", year);
        } else
            printf("%d is a leap year.", year);
    } else
        printf("%d is not a leap year.", year);

    return 0;
}