#include<iostream>
#include<utility>
using namespace std;

int judge(pair<double, double> p1, pair<double, double> p2){
	double S = p1.first*p2.second - p2.first*p1.second;
	if (0 < S) return 1;
	if (0 > S) return -1;
	if (0 == S) return 0;
}

int main(){
	pair<double, double> A, B, C, P;

	while (cin >> A.first >> A.second >> B.first >> B.second >> C.first >> C.second >> P.first >> P.second){
		pair<double, double> AB, BC, CA, AP, BP, CP;
		AB = { B.first - A.first, B.second - A.second };
		BC = { C.first - B.first, C.second - B.second };
		CA = { A.first - C.first, A.second - C.second };
		AP = { P.first - A.first, P.second - A.second };
		BP = { P.first - B.first, P.second - B.second };
		CP = { P.first - C.first, P.second - C.second };
		
		if (judge(AP, AB) == judge(BP, BC) && judge(BP, BC) == judge(CP, CA) && judge(CP, CA) == judge(AP, AB)){
			cout << "YES" << endl;
		}
		else{
			cout << "NO" << endl;
		}
	}

	return 0;
}
