#include<iostream>
#include<utility>
#include<cmath>
using namespace std;
double a;
pair<double,double>f()
{
	double ta=a,b,c,d;
	cin>>b>>c>>d>>a;
	return make_pair(c-ta,d-b);
}
double g(pair<double,double>p,pair<double,double>q)
{
	return p.first*q.first+p.second*q.second;
}
main()
{
	cin>>a;
	while(cin)
	{
		cout<<(abs(g(f(),f()))<1e-10?"YES":"NO")<<endl;
	}
}

