#include <iostream>

int main()
{
	long double x1, y1, x2, y2, x3, y3, x4, y4;
	while (std::cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4) {
		long double inner_product = (x2-x1) * (x4-x3) + (y2-y1) * (y4-y3);
		if (inner_product==0.0) std::cout << "YES" << std::endl;
		else std::cout << "NO" << std::endl;
	}
	return 0;
}
