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

int main() {
  double x1,y1,x2,y2,x3,y3,x4,y4;
  
  while( cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4 ) {
    if ( x2-x1 == 0.0 ) {
      if( y4-y3 == 0.0 ) goto ok;
      else goto ng;
    }
    if ( y2-y1 == 0.0 ) {
      if( x4-x3 == 0.0 ) goto ok;
      else goto ng;
    }
    
    if (( y2-y1 ) / ( x2-x1 ) == - ( x4-x3 ) / ( y4-y3 )) goto ok;
    else goto ng;
    
    cerr << "FAIL" << endl;
    exit(EXIT_FAILURE);
    
  ok:
    cout << "YES" << endl;
    continue;
  ng:
    cout << "NO" << endl;
  }
  
  return 0;
}