#include <iostream>
using namespace std;
int main()
{
  double ax,ay,bx,by,cx,cy,dx,dy,r1,r2;
  while(cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy){
    if(bx-ax == 0){
      if(dy-cy == 0) cout << "YES" << endl;
      else cout << "NO" << endl;
    }else if(dx-cx == 0){
      if(by-ay == 0) cout << "YES" << endl;
      else cout << "NO" << endl;
    }else{
      r1 = (by-ay) / (bx-ax);
      r2 = (dy-cy) / (dx-cx);
      if(r1 * r2 == -1) cout << "YES" << endl;
      else cout << "NO" << endl;
    }
  }
  return 0;
}