/*#include <iostream>
using namespace std;

int main(){
	double a[8];
	while(cin >>a[0]>>a[1]>>a[2]>>a[3]>>a[4]>>a[5]>>a[6]>>a[7]){
		if((a[3]-a[1])*(a[7]-a[5])==-1*(a[2]-a[0])*(a[6]-a[4]))cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}*/
#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((yb-ya)*(yd-yc)==-1*(xb-xa)*(xd-xc)) cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}