#include<iostream>
using namespace std;

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