#include <iostream>
using namespace std;

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

	while(!cin.eof()){
		int sign1=(((x2-x1)*(yp-y1)-(xp-x1)*(y2-y1))>0)?1:0;
		int sign2=(((x3-x2)*(yp-y2)-(xp-x2)*(y3-y2))>0)?1:0;
		int sign3=(((x1-x3)*(yp-y3)-(xp-x3)*(y1-y3))>0)?1:0;
		//cout << sign1 << sign2 << sign3;
		if(sign1==sign2 && sign2==sign3)
			cout << "YES\n";
		else
			cout << "NO\n";

		cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> xp >> yp;

	}
}