#include <iostream>
#include <cfloat>
#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 + ( 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(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 a.x*b.x + a.y*b.y; }
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;
  
  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;
}