#include<iostream>
#include<cfloat>
#include<cassert>
#include<cmath>
#include<vector>
 
using namespace std;
 
#define EPS (1e-10)
#define equals(a, b) (fabs((a) - (b)) < EPS )
#define dle(a, b) (equals(a, b) || a < b )
static const double PI = acos(-1);
 
class Point{
    public:
    double x, y;
     
    Point ( double x = 0, double y = 0): x(x), y(y){}
     
    Point operator + ( const Point &p ) const { return Point(x + p.x, y + p.y); }
    Point operator - ( const Point &p ) const { return Point(x - p.x, y - p.y); }
    Point operator * ( const 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 x != p.x ? x < p.x : y < p.y;
    }
 
    bool operator == ( const Point &p ) const {
    return fabs(x-p.x) < EPS && fabs(y-p.y) < EPS;
    }
};
 
typedef Point Vector;
 
class Segment{
    public:
    Point p1, p2;
    Segment(Point s = Point(), Point t = Point()): p1(s), p2(t){}
};
 
double norm( Vector a ){ return a.x*a.x + a.y*a.y; }
double abs( Vector a ){ return sqrt(norm(a)); }
double getDistance( Vector a, Vector b ){ return abs(a - b); }
double dot( Vector a, Vector b ){ return a.x*b.x + a.y*b.y; }
double cross( Vector a, Vector b ){ return a.x*b.y - a.y*b.x; }
 
static const int COUNTER_CLOCKWISE = 1;
static const int CLOCKWISE = -1;
static const int ONLINE_BACK = 2;
static const int ONLINE_FRONT = -2;
static const int ON_SEGMENT = 0;
 
int ccw( Point p0, Point p1, Point p2 ){
    Vector a = p1 - p0;
    Vector b = p2 - p0;
    if ( cross(a, b) > EPS ) return COUNTER_CLOCKWISE;
    if ( cross(a, b) < -EPS ) return CLOCKWISE;
    if ( dot(a, b) < -EPS ) return ONLINE_BACK;
    if ( norm(a) < norm(b) ) return ONLINE_FRONT;
    return ON_SEGMENT;
}
 
int main(){
    double x1, y1, x2, y2, x3, y3, x, y;
    Segment S[3];
 
    while ( cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x >> y ){
    int ccw1 = ccw( Point(x1, y1), Point(x2, y2),  Point(x, y) );
    int ccw2 = ccw( Point(x2, y2), Point(x3, y3),  Point(x, y) );
    int ccw3 = ccw( Point(x3, y3), Point(x1, y1),  Point(x, y) );
    if ( ccw1 == ccw2 && ccw2 == ccw3 ) cout << "YES" << endl;
    else cout << "NO" << endl;
    }
    return 0;
}