Leap year is defined as a year that divisible by 400 or not divisible by 100 but divisible by 4.

#include <iostream>using namespace std;


int main(){
    int y;
    cin>>y;
    if((y%4==0&&y%100!=0)||y%400==0) cout<<"yes"<<endl;
    else cout<<"no"<<endl;
    return 0;
}

:D