#include <iostream>
using namespace std;

double getInner( double x1, double y1, double x2, double y2 )
{
	return x1 * x2 + y1 * y2;
}

int main( void )
{
	double xA, yA, xB, yB, xC, yC, xD, yD;
	while ( cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD )
	{
		// ÎIÈÀWÉ¼·
		double x, y;

		x = xA; y = yA;
		xA = xA - x;
		yA = yA - y;
		xB = xB - x;
		yB = yB - y;

		x = xC; y = yC;
		xC = xC - x;
		yC = yC - y;
		xD = xD - x;
		yD = yD - y;

		double d = getInner( xB, yB, xD, yD );
		if ( d == 0.0 )
		{
			cout << "YES" << endl;
		}
		else
		{
			cout << "NO" << endl;
		}

	}

	return 0;
}