#include <iostream>
using namespace std;
int main() {
	float xA,yA,xB,yB,xC,yC,xD,yD;
	while (cin>>xA>>yA>>xB>>yB>>xC>>yC>>xD>>yD) {
		if ((xA==xB&&yC==yD)||(yA==yB&&xC==xD)) {
			cout << "YES" << endl;
			continue;
		} else if (xA==xB||yC==yD||yA==yB||xC==xD) {
			cout << "NO" << endl;
			continue;
		}
		double AB = (yA-yB)/(xA-xB);
		double CD = (yC-yD)/(xC-xD);
		if (-1*AB==CD) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}