#include<iostream>
using namespace std;

int main()
{
	double x[4], y[4];

	while (cin>>x[0]>>y[0]>>x[1]>>y[1]>>x[2]>>y[2]>>x[3]>>y[3]) {
		if ( (y[0]-y[1])*(y[2]-y[3]) == (x[0]-x[1])*(x[3]-x[2]) ) cout<<"YES"<<endl;
			else cout<<"NO"<<endl;
	}
	return 0;
}