#include <iostream>

using namespace std;

int main(){
  double x1,x2,x3,x4,y1,y2,y3,y4;
  while( cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4){

    if((x2 - x1)*(x4 - x3)+(y2 - y1)*(y4 - y3) < 10e-12)cout << "YES" << endl;
      else cout << "NO" << endl;
  }
}