#include <iostream>
using namespace std;
 
int main(){
    double xa, ya;
    double xb, yb;
    double xc, yc;
    double xd, yd;
    while(cin >> xa >> ya >> xb >> yb
        >> xc >> yc >> xd >> yd)
    {
        double dx1 = xb - xa, dy1 = yb - ya;
        double dx2 = xd - xc, dy2 = yd - yc;
        if(dx1 * dx2 + dy1 * dy2 == 0){
            cout << "YES" << endl;
        } else {
            cout <<"NO" << endl;
        }
    }
    return 0;
}