#include <iostream>
#include <cmath>
using namespace std;

#define EPS 1e-12

int main()
{
	double xa,ya,xb,yb,xc,yc,xd,yd;
	while(cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd){
		if( abs((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc)) <= EPS){
			cout << "YES"<<endl;
		}else{
			cout<< "NO"<<endl;
		}
	}
	return 0;
}