#include "bits/stdc++.h"
#include <iostream>
using namespace std;
double EPS = 1e-10;

int main() {

	complex<double> a, b, c, d, e, f;
	while (cin >> a.real() >> a.imag() >> b.real() >> b.imag() >> c.real()
			>> c.imag() >> d.real() >> d.imag()) {
		e = a - b;
		f = c - d;
		if (e.real() * f.real() + e.imag() * f.imag() < EPS) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}