#include <iostream>
using namespace std;

int main(){
	int xa,xb,xc,xd,ya,yb,yc,yd;
	double a,b,c,d,e,f,g,h;
	while(cin >> a >> b >> c >> d >> e >> f >> g >> h){
		xa = a * 10;
		ya = b * 10;
		xb = c * 10;
		yb = d * 10;
		xc = e * 10;
		yc = f * 10;
		xd = g * 10;
		yd = h * 10;
		if(((xb - xa) * (xd - xc)) + ((yb - ya) * (yd - yc)) == 0) cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}