#include<iostream>
using namespace std;

int main() {
  double xA, yA, xB, yB, xC, yC, xD, yD, gradA, gradB;
  while(cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD){
    gradA = (yB-yA)/(xB-xA);
    gradB = (yD-yC)/(xD-xC);
    if( ((gradA/gradB) == -1.0) || ( (yA == yB) && (xC == xD) ) || ( (yC == yD) && (xA == xB) ) ) 
      cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}