#include <iostream>

#define rep(i,n) for(int i=0;i<n;i++)

using namespace std;

int main()
{
	double *a = new double[8];
	while(cin >> a[0])
	{
		rep(i,7) cin >> a[i+1];

		if((a[2]-a[0])*(a[6]-a[4])+(a[3]-a[1])*(a[7]-a[5]) == 0)
		{
			cout << "YES" << endl;
		}
		else
		{
			cout << "NO" << endl;
		}
	}
	return 0;
}