#include<iostream>
using namespace std;

int main(){

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

  while(cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){

    if(yb - ya == 0 && xd - xc == 0) cout << "YES" << endl;
    else if(xb - xa == 0 && yd - yc == 0) cout << "YES" << endl;
    else if((yb - ya)/(xb - xa) == -((xd - xc)/(yd - yc))) cout << "YES" << endl;
    else cout << "NO" << endl;

  }
}