#include <iostream>

using namespace std;

int main(void){

  double xa,ya,xb,yb,xc,yc,xd,yd;

  while( cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd ){
    if( (xa-xb)*(xc-xd) + (ya-yb)*(yc-yd) == 0 ) cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}