#include <iostream>
#include <cmath>

using namespace std;

bool is_orth(double xa, double ya, double xb, double yb, double xc, double yc, double xd, double yd) {

    double inner_product = (xa-xb)*(xc-xd) + (ya-yb)*(yc-yd);
    return fabs(inner_product) < 1e-10;
}

int main() {
    double xa, ya, xb, yb, xc, yc, xd, yd;
    string result;
    while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd) {
        if(is_orth(xa, ya, xb, yb, xc, yc, xd, yd)) {
            result = "YES";
        } else {
            result = "NO";
        }
        cout << result << endl;
    }
    return 0;
}