#include<iostream>
#include<algorithm>
using namespace std;
typedef long double LD;

int main() {
	LD a, b, c, d, e, f, g, h;
	while (cin >> a >> b >> c >> d >> e >> f >> g >> h) {
		LD i = (h-f)*(d - b);
		LD j = (c - a)*(g-e);
		if (i+j==0)cout << "YES" << endl;
		else cout << "NO" << endl;
		
	}
	return 0;
}