#include stdio.h

int main() {
    int year = 2023;
    if (year % 4 == 0) {
        if (year % 100 == 0) {
            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;
}

What is the output of the program