#include<iostream>
using namespace std;
int main() {
	double x1, y1, x2, y2, x3, y3, x4, y4;
	while (cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4){
		if ((x1 == x2&&y3 == y4) || (x3 == x4&&y1 == y2))
			cout << "YES\n";
		else if (x1 == x2 || x3 == x4 || y1 == y2 || y3 == y4)cout << "NO\n";
		else if ((y1 - y2) / (x1 - x2)*(y3 - y4) / (x3 - x4)+1 < 0.00001)cout << "YES\n";
		else cout << "NO\n";
	}
}