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

#define EPS 1e-9

int main(){
  double ax,ay,bx,by,cx,cy,dx,dy;
  double AX, AY, BX, BY, A, B;
  while(cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy){
    AX = ax-bx;
    AY = ay-by;
    BX = cx-dx;
    BY = cy-dy;
    A = AY/AX;
    B = BY/BX;
    if(AX == 0){
      if(BY == 0)cout << "YES" << endl;
      else cout << "NO" << endl;
      continue;
    }
    else if(BX == 0){
      if(AY == 0)cout << "YES" << endl;
      else cout << "NO" << endl;
      continue;
    }
    else cout << (A*B==-1?"YES":"NO") << endl;
  }
  return 0;
}