#include "bits/stdc++.h"
#define REP(i,n,N) for(ll i=(n); i<(N); i++)
#define RREP(i,n,N) for(ll i=(N-1); i>=n; i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define p(s) cout<<(s)<<endl
#define p2(a,b) cout<<(a)<<" "<<(b)<<endl
#define v2(T) vector<vector<T>>
typedef long long ll;
using namespace std;
const ll inf=1e18;
const ll NODE_SIZE = 60;

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() {
    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;

    return 0;
}