// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0012

#include <iostream>
using namespace std;

int main() {
	double x1, y1, x2, y2, x3, y3, xp, yp;

	while (cin >> x1 >> y1
		       >> x2 >> y2 
		       >> x3 >> y3
		       >> xp >> yp) {

		double l1_x = (y2 - y3);
		double l1_y = -(x2 - x3);
		double l1_c = -(y2 - y3)*x3 + y3;
		
		double l2_x = (y1 - y3);
		double l2_y = -(x1 - x3);
		double l2_c = -(y1 - y3)*x3 + y3;

		double l3_x = (y1 - y2);
		double l3_y = -(x1 - x2);
		double l3_c = -(y1 - y2)*x2 + y2;

		if ((l1_x * xp + l1_y * yp + l1_c)*l1_c >= 0 &&
			(l2_x * xp + l2_y * yp + l2_c)*l2_c >= 0 &&
			(l3_x * xp + l3_y * yp + l3_c)*l3_c >= 0)
			cout << "YES" << endl;
		else
			cout << "NO" << endl;
	}

	return 0;
}