#include <iostream>
using namespace std;

int main(){
	double a,b,c,d,e,f,g,h;
	while(cin >> a >> b >> c >> d >> e >> f >> g >> h){
		if(((c - a) * (g- e)) + ((d - b) * (h - f)) == 0) cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}