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

int main( ) {
  double ax,ay,bx,by,cx,cy,dx,dy;
  while(cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy) {
    if(fabs((ax-bx)*(cx-dx)+(ay-by)*(cy-dy))<1e-10) cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}
