#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <climits>

using namespace std;

double EPS = 1e-10;

int main() {
	double ax, ay, bx, by, cx, cy, dx, dy;

	while( cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy ) {
		bx -= ax; by -= ay;
		dx -= cx; dy -= cy;

		if( abs((bx * dx) + (by * dy)) < EPS ) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}