#include <iostream>
#include <cstdio>
using namespace std;

struct point
{
	double x, y;
};

int main() {
	point p[4];
	while (true){
		for (int i = 0; i < 4; i++){
			if (scanf("%lf%lf", &p[i].x, &p[i].y) == EOF) return 0;
		}
		//cout << (p[1].x - p[0].x) * (p[3].x - p[2].x) + (p[1].y - p[0].y) * (p[3].y - p[2].y) << endl;
		if ((p[1].x - p[0].x) * (p[3].x - p[2].x) + 
		    (p[1].y - p[0].y) * (p[3].y - p[2].y) == 0.00){
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
}