#define _USE_MATH_DEFINES
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <cstdlib>
#include <cmath>

using namespace std;
double EPS = 1e-10;

void q58() {
	double ax, ay, bx, by, cx, cy, dx, dy;
	for (; cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy;) {

		if (abs((ay - by) * (cy - dy) + (cx - dx)*(ax - bx)) <EPS) {
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
}
int main() {
	q58();
	return 0;
}