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

int main()
{
	double EPS=1e-12;
	double *a = new double[8];
	while(cin>>a[0]>>a[1]>>a[2]>>a[3]>>a[4]>>a[5]>>a[6]>>a[7])
	{
		if(fabs(((a[2]-a[0])*(a[6]-a[4]))+((a[3]-a[1])*(a[7]-a[5]))) <= EPS)
		{
			cout<<"YES" << endl;
		}
		else 
		{
			cout<< "NO" << endl;
		}
	}
	return 0;
}