#include <cstdio>
#include <iostream>
using namespace std;
int main() {
	double xA, yA, xB, yB, xC, yC, xD, yD;
	while(cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD) {
		if((xA - xB) * (xC - xD) + (yA - yB) * (yC - yD) == 0) {
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
}