#include <iostream>
using namespace std;

int main()
{
	double xa, ya, xb, yb, xc, yc, xd, yd, x1, y1, x2, y2;

	while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){
		x1 = xa - xb;
		y1 = ya - yb;
		x2 = xc - xd;
		y2 = yc - yd;
		if ( y2 / x2 == -1 / y1 / x1 || (y1 == 0 && x2 == 0) || (x1 == 0 && y2 == 0)){
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
	return (0);
}