#include <cstdio>
#include <iostream>
using namespace std;
int main(void){
  double a,b,c,d,e,f,g,h;
  while(cin >> a >> b >> c >> d >> e >> f >> g >> h){
    if( (b-d)*(f-h) + (e-g)*(a-c) ) cout << "NO" << endl;
    else cout << "YES" << endl;
  }
}