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

int main(){
  double xa,ya,xb,yb,xc,yc,xd,yd,xan,yan,xanan,yanan;

  while(cin >>  xa>> ya>>xb>>yb>>xc>>yc>>xd>>yd){
      xan=xb-xa;
      yan=yb-ya;
      xanan=xd-xc;
      yanan=yd-yc;
      if((xan*xanan + yan*yanan )==0){
cout << "YES" << endl;
 
      }else{
   cout << "NO" << endl;
 
      }
    }


  



  return 0;

}