#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <sstream>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <numeric>
#include <cmath>
#include <climits>
#include <limits>
#include <cfloat>
#include <fstream>
using namespace std;

int main()
{
//	cut here before submit 
//	freopen("testcase.pt", "r", stdin);
	string str = "";

	while (getline (cin, str )){
		int i;
		vector <double> tpx (3, 0.);
		vector <double> tpy (3, 0.);
		double px = 0.;
		double py = 0.;
	
		stringstream ss(str);

		for (i = 0; i < 3; ++i){
			double tx,ty;
			ss >> tx >> ty;
			tpx[i] = tx; tpy[i] = ty;
		} // end for
		ss >> px >> py;

		vector <double> a(3, 0.);
		vector <double> b(3, 0.);
		vector <double> c(3, 0.);
/*
		for (i = 0; i < 3; ++i){
			cout << "tp[" << i << "]: ";
			cout << '(' << tpx[i] << ',' << tpy[i] << ')' << endl;
		} // end for
		cout << "p: ";
		cout << '(' << px << ',' << py << ')' << endl;
*/
		int j;
		for (i = 0; i < 3; ++i){
			j = (i + 1) % 3;
			if (tpx[i] == tpx[j]){
				a[i] = 1.0;
				b[i] = 0.0;
				c[i] = -a[i]*tpx[i] - b[i]*tpy[i];
			}else if (tpy[i] == tpy[j]){
				a[i] = 0.0;
				b[i] = 1.0;
				c[i] = -a[i]*tpx[i] - b[i]*tpy[i];
			}else{
				a[i] = (tpy[j] - tpy[i]);
				b[i] = -(tpx[j] - tpx[i]);
 				c[i] = -a[i]*tpx[i] - b[i]*tpy[i];
			} // end if
//			cout << a[i] << ' ' << b[i] << ' ' << c[i] << endl;
		} // end for
		vector <double> d(3, 0.0);

		for (i = 0; i < 3; ++i){
			d[i] = a[i]*px + b[i]*py + c[i];
//			cout << "d[" << i << "]: " << d[i] << endl;
		} // end for

		int plus = 0;
		int minus = 0;
		for (i = 0; i < 3; ++i){
			if (d[i] > 0){
				++plus;
			}else{
				++minus;
			} // end if
		} // end for

		if (plus == 1 && minus == 2){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		} // end if
			
	} // end for
		
	return 0;
}