#include <iostream>
#include <vector>
#include <algorithm>
#include <complex>

using namespace std;

int main(){

	double x1,y1,x2,y2,x3,y3,xp,yp;

	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>xp>>yp){
		complex<double> p1(x1,y1);
		complex<double> p2(x2,y2);
		complex<double> p3(x3,y3);
		
		// p1_2xNgÆp1_3xNgðßA»êçÅpxNgð çíµ½Æ«ÌWÅ»f
		complex<double> p12 = -p1 + p2;
		complex<double> p13 = -p1 + p3;

		double a = (xp - (p13.real()*yp)/p13.imag())/(p12.real() - (p13.real()*p12.imag())/(p13.imag()));
		double b = (yp - a*p12.imag())/p13.imag();
		if(a >= 0 && b >= 0 && a + b <= 1)
			cout << "YES" << endl;
		else
			cout << "NO" << endl;
	}

	return 0;
}