#define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
#include <random>
//#include "util.k"

using namespace std;

//呪文
#define DUMPOUT cout
#define dump(...) DUMPOUT<<"  ";DUMPOUT<<#__VA_ARGS__<<" :["<<__LINE__<<":"<<__FUNCTION__<<"]"<<endl;DUMPOUT<<"    ";dump_func(__VA_ARGS__)

typedef unsigned uint; typedef long long ll; typedef unsigned long long ull; typedef pair<int, int> pii; typedef pair<ll, ll> pll; typedef pair<double, double> pdd; typedef pair<string, string> pss;
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const pair<_KTy, _Ty>& m) { ostr << "{" << m.first << ", " << m.second << "}"; return ostr; }
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const map<_KTy, _Ty>& m) { if (m.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << *m.begin(); for (auto itr = ++m.begin(); itr != m.end(); itr++) { ostr << ", " << *itr; } ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { ostr << ", " << *itr; }	ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const set<_Ty>& s) { if (s.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << *(s.begin()); for (auto itr = ++s.begin(); itr != s.end(); itr++) { ostr << ", " << *itr; }	ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const stack<_Ty>& s) { if (s.empty()) { ostr << "{ }"; return ostr; } stack<_Ty> t(s); ostr << "{" << t.top(); t.pop(); while (!t.empty()) { ostr << ", " << t.top(); t.pop(); } ostr << "}";	return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const list<_Ty>& l) { if (l.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << l.front(); for (auto itr = ++l.begin(); itr != l.end(); ++itr) { ostr << ", " << *itr; } ostr << "}"; return ostr; }
template <typename _KTy, typename _Ty> istream& operator >> (istream& istr, pair<_KTy, _Ty>& m) { istr >> m.first >> m.second; return istr; }
template <typename _Ty> istream& operator >> (istream& istr, vector<_Ty>& v) { for (size_t i = 0; i < v.size(); i++) istr >> v[i]; return istr; }
namespace aux { // print tuple
	template<typename Ty, unsigned N, unsigned L> struct tp { static void print(ostream& os, const Ty& v) { os << get<N>(v) << ", "; tp<Ty, N + 1, L>::print(os, v); } };
	template<typename Ty, unsigned N> struct tp<Ty, N, N> { static void print(ostream& os, const Ty& value) { os << get<N>(value); } };
}
template<typename... Tys> ostream& operator<<(ostream& os, const tuple<Tys...>& t) { os << "{"; aux::tp<tuple<Tys...>, 0, sizeof...(Tys)-1>::print(os, t); os << "}"; return os; }

template<typename A, size_t N, typename T> inline void Fill(A(&array)[N], const T &val) { std::fill((T*)array, (T*)(array + N), val); }

void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head&& head, Tail&&... tail) { DUMPOUT << head; if (sizeof...(Tail) == 0) { DUMPOUT << " "; } else { DUMPOUT << ", "; } dump_func(std::move(tail)...); }

#define PI 3.14159265358979323846
#define EPS 1e-11
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define all(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define fake false



namespace NVec3 {

	struct Vec3 {
		double v[3];
		Vec3() { v[0] = v[1] = v[2] = 0; }
		Vec3(double x, double y, double z) { v[0] = x; v[1] = y; v[2] = z; }

		double& operator[] (size_t n) & { return v[n]; }
		const double& operator[] (size_t n) const& { return v[n]; }
		double operator[] (size_t n) const&& { return move(v[n]); }

		Vec3& operator+=(const Vec3& w) { v[0] += w[0]; v[1] += w[1]; v[2] += w[2]; return *this; }
		Vec3& operator-=(const Vec3& w) { v[0] -= w[0]; v[1] -= w[1]; v[2] -= w[2]; return *this; }
		double operator*=(const Vec3& w) { return v[0] * w[0] + v[1] * w[1] + v[2] * w[2]; }
		template<typename T> Vec3& operator/=(const T& x) { v[0] /= x; v[1] /= x; v[2] /= x; return *this; }

		friend istream& operator >> (istream& is, Vec3& v) { is >> v[0] >> v[1] >> v[2]; return is; }
		friend ostream& operator << (ostream& os, Vec3& v) { os << "{" << v[0] << ", " << v[1] << ", " << v[2] << "}"; return os; }

		double length() { return sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]); }
	};

	Vec3 operator+(const Vec3& t1, const Vec3& t2) { return Vec3(t1) += t2; }
	Vec3 operator-(const Vec3& t1, const Vec3& t2) { return Vec3(t1) -= t2; }
	double operator*(const Vec3& t1, const Vec3& t2) { return Vec3(t1) *= t2; }
	template<typename T> Vec3 operator/(const Vec3& t, const T& x) { return Vec3(t) /= x; }

	Vec3 cross_product(const Vec3& v1, const Vec3& v2) {
		return Vec3(
			v1[1] * v2[2] - v1[2] * v2[1],
			v1[2] * v2[0] - v1[0] * v2[2],
			v1[0] * v2[1] - v1[1] * v2[0]
		);
	}

}

int main() {

	//clock_t start, end;
	//start = clock();

	using namespace NVec3;

	Vec3 A, B, C, D;
	cin >> A >> B >> C >> D;
	
	Vec3 n = cross_product(B - A, C - A);
	Vec3 m1 = cross_product(n, B - A);
	Vec3 m2 = cross_product(n, C - B);
	Vec3 m3 = cross_product(n, A - C);

	if (m1 * (D - A) > 0 && m2 * (D - B) > 0 && m3 * (D - C) > 0)
		cout << "YES" << endl;
	else
		cout << "NO" << endl;	

	//end = clock();
	//printf("%d msec.\n", end - start);

	return 0;
}