#include<iostream>
#include<fstream>
#include<sstream>
#include<string>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<list>
#include<algorithm>
#include<utility>
#include<complex>

using namespace std;

#define reE(i,a,b) for(auto (i)=(a);(i)<=(b);(i)++)
#define rE(i,b) reE(i,0,b)
#define reT(i,a,b) for(auto (i)=(a);(i)<(b);(i)++)
#define rT(i,b) reT(i,0,b)
#define rep(i,a,b) reE(i,a,b);
#define rev(i,a,b) for(auto (i)=(b)-1;(i)>=(a);(i)--)
#define fe(i,b) for (auto &(x):b);
#define itr(i,b) for(auto (i)=(b).begin();(i)!=(b).end();++(i))
#define rti(i,b) for(auto (i)=(b).rbegin();(i)!=(b).rend();++(i))
#define LL long long
#define all(b) (b).begin(),(b).end()

#define input_init stringstream ss; string strtoken, token; istringstream is
#define input_line  getline(cin, strtoken);is.str(strtoken);is.clear(istringstream::goodbit)
#define input_token(num) ss.str(""); ss.clear(stringstream::goodbit); getline(is, token, ','); ss << token; ss >> num

#define dir(xx,yy,x,y,i)(xx)=(x)+dir[(i)],(yy)=(y)+dir[(i)+1];

typedef complex<double> P;
typedef vector< P > Poly;

const LL INF = 1 << 30;
const double eps = 1e-8;
const int dir[] = { 0, 1, 0, -1, 0 };

inline double dot(const P a, const  P b){//A dot B
	return a.real()*b.real() + a.imag()*b.imag();
}

inline double cross(const P a, const P b){//A cross B
	return a.real()*b.imag() - a.imag()*b.real();
}




int operator<(const P& l, const P& r){
	if (l.real() == r.real())
		return(l.imag() < r.imag());
	return(l.real() < r.real());
}

inline void convex_hull(Poly& p, Poly& res){
	int k = 0, t;
	res.clear();
	res.resize(2 * p.size());
	//sort(all(p));
	reT(i, 0, (int)p.size()){
		while (k > 1 && (cross(res[k - 1] - res[k - 2], p[i] - res[k - 1])<eps))k--;
		res[k++] = p[i];
	}
	t = k;
	rev(i, 0, (int)p.size() - 1){
		while (k > t && (cross(res[k - 1] - res[k - 2], p[i] - res[k - 1])<eps))k--;
		res[k++] = p[i];
	}
	res.resize(k - 1);
}

inline bool convex_in(const Poly& l, const P& p){
	int a = 0, b = (int)l.size(), c;
	double A, C;
	const P g = (l[a] + l[b - 1] + l[b / 2]) / 3.0;
	while (b - a > 1){
		c = (a + b) / 2;
		A = cross(l[a] - g, p - l[a]);
		C = cross(l[c] - g, p - l[c]);
		if (cross(l[a] - g, l[c] - g) >= 0){
			if (A>-eps&&C < -eps)b = c;
			else a = c;
		}
		else {

			if (C < -eps || A > -eps)b = c;
			else a = c;
		}
	}
	return(cross(l[b%l.size()] - l[a], p - l[b%l.size()]) > -eps);
}

inline double convex_area(const Poly& l){
	double res = 0;
	reT(i, 2, (int)l.size()){
		res += abs(cross(l[1] - l[0], l[i] - l[1]));
	}
	return res;
}


int main(void){
	pair<double,double> xy[5];

	Poly ppp;
	Poly res;
	for (int i = 0; i < 5; i++){
		cin >> xy[i].first >> xy[i].second;

	}
	sort(xy, xy + 5);
	for (int i = 0; i < 5; i++){
		P pppp;
		pppp.real(xy[i].first);
		pppp.imag(xy[i].second);
		ppp.push_back(pppp);
	}
	convex_hull(ppp, res);
	if (res.size() == 5)cout << "YES" << endl;
	else cout<<"NO" << endl;

	return(0);
}