#include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define rep(i,n) for(int i=0;i<n;i++)
constexpr int INF = numeric_limits<int>::max()/2;
constexpr long long LINF = numeric_limits<long long>::max()/3;
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
//struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double{ double d; explicit Double(double x) : d(x){} };
ostream& operator<<(ostream& os,const Double x){ os << fixed << setprecision(20) << x.d; return os; }
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
template<typename T> ostream& operator<<(ostream& os,const set<T>& st){ os<<"{"; for(T v:st) os<<v<<","; os <<"}"; return os; }
template<typename T,typename U> inline void chmax(T &x,U y){ if(y>x) x = y; }
template<typename T,typename U> inline void chmin(T &x,U y){ if(y<x) x = y; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }
//constexpr double eps = 1e-14; 
constexpr double eps = 1e-10; 
constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/

constexpr double EPS = 1e-9;

//???
class Point{
public:
    double x,y;
    Point (double x=0,double y=0) : x(x),y(y){}

    Point operator + (Point p){ return Point( x+p.x , y-p.y );}
    Point operator - (Point p){ return Point( x-p.x , y-p.y ); }
    Point operator * (double a){ return Point( a*x , a*y ); }
    Point operator / (double a){ return Point( x/a , y/a ); }

    double abs(){   //??§??????
        return sqrt(norm());
    }

    double norm(){  //?????????
        return x*x+y*y;
    }

    bool operator == (const Point &p) const{
        return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
    }
};

using Vector = Point;

double cross(Vector a,Vector b){ return a.x*b.y-a.y*b.x; }

void solve(Point p1,Point p2,Point p3,Point pin){

    //cout << p1.x << " " << p1.y << " " << p2.x << " " <<p2.y << " " <<p3.x << " " << p3.y << " " << pin.x << " " <<pin.y << endl;

    bool ok = true;
    Point p[3] = {p1,p2,p3};

    for(int i=0;i<3;i++){
        Vector v1 = Vector(p[(i+1)%3]-p[i]);
        Vector v2 = Vector(p[(i+2)%3]-p[i]);
        Vector vin = Vector(pin-p[i]);

        double c1 = cross(v1,vin);
        double c2 = cross(v1,v2);
        if(c1*c2 < -EPS) ok=false;
    }
    if(ok) cout << "YES" << endl;
    else cout << "NO" << endl;
}

int main(){
    while(true){
        double x1,x2,x3,xin,y1,y2,y3,yin;
        cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> xin >> yin;
        if(cin.eof()) break;
        solve(Point(x1,y1),Point(x2,y2),Point(x3,y3),Point(xin,yin));
    }
}