#include<iostream>
using namespace std;

int main() {
	long double a, b, c, d, e, f, g, h;
	while (cin >> a >> b >> c >> d >> e >> f >> g >> h) {
		if (a == c) {
			if (f == h)cout << "YES" << endl;
			else cout << "NO" << endl;
		}
		else {
			long double ka = (d - b) / (c - a);
			long double kb = (h - f) / (g - e);
			if (ka*kb == -1)cout << "YES" << endl;
			else cout << "NO" << endl;
		}
	}
	return 0;
}