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

#define EPS 1e-10

int main() {
  double x1,y1,x2,y2,x3,y3,x4,y4;
  
  while( cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4 ) {
    if ( fabs( (x1-x2)*(x3-x4) + (y1-y2)*(y3-y4) ) < EPS ) cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  
  return 0;
}