//Orthogonal
#include<bits/stdc++.h>
using namespace std;

const double EPS=1E-10;

int main(){
  complex<double> a, b, c, d;
  while(cin>>a.real()>>a.imag()>>b.real()>>b.imag()>>c.real()>>c.imag()>>d.real()>>d.imag()){
    complex<double> v1=a-b, v2=c-d;
    if((v1.real()*v2.real()+v1.imag()*v2.imag())<EPS)cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
  }
  return 0;
}