#include<iostream>

int main() {
	double x1, y1, x2, y2, x3, y3, xp, yp;
	while (std::cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> xp >> yp) {
		double ax, ay, bx, by, s, t;
		ax = x2 - x1; ay = y2 - y1;
		bx = x3 - x1; by = y3 - y1;
		// sa + tb = p - ra
		// sax + tbx = xp - x1
		// say + tby = yp - y1
		s = (yp - y1 - ((xp - x1) / bx)) / (ay - (ax / bx));
		t = (xp - x1 - (s * ax)) / bx;
		if (s > 0 && t > 0 && s + t < 1) std::cout << "YES" << std::endl;
		else std::cout << "NO" << std::endl;
	}
	return 0;
}