#include <iostream>
using namespace std;

int main(){
    double x[4];
    double y[4];

    while(cin >> x[0] >> y[0] >> x[1] >> y[1] >> x[2] >> y[2] >> x[3] >> y[3]){
        double xv1 = x[1] - x[0];
        double yv1 = y[1] - y[0];
        double xv2 = x[3] - x[2];
        double yv2 = y[3] - y[2];
        cout << ((xv1*xv2+yv1*yv2==0.0)?"YES":"NO") << endl;
    }

    return 0;
}