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

int main()
{
	double xa, ya, xb, yb, xc, yc, xd, yd;

	while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){

		if ((yb - ya) * (yd - yc) == -1 * (xb - xa) * (xd - xc)){
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}

	}

	return (0);
}