// 2011/04/04 Tazoe

#include <iostream>
using namespace std;

int main()
{
	while(true){
		double xA, yA, xB, yB, xC, yC, xD, yD;
		cin >> xA;
		if(cin.eof())
			break;
		cin >> yA >> xB >> yB >> xC >> yC >> xD >> yD;

		double xAB = xB-xA;
		double yAB = yB-yA;
		double xCD = xD-xC;
		double yCD = yD-yC;

		if(xAB*xCD+yAB*yCD==0.0)
			cout << "YES" << endl;
		else
			cout << "NO" << endl;
	}

	return 0;
}