/* {{{ Shinobu kawaii */
/*
  ______   __        _                  __                 
.' ____ \ [  |      (_)                [  |                
| (___ \_| | |--.   __   _ .--.   .--.  | |.--.   __   _   
 _.____`.  | .-. | [  | [ `.-. |/ .'`\ \| '/'`\ \[  | | |  
| \____) | | | | |  | |  | | | || \__. ||  \__/ | | \_/ |, 
 \______.'[___]|__][___][___||__]'.__.'[__;.__.'  '.__.'_/ 

*/
/* }}} */

#include <bits/stdc++.h>
using namespace std;

// #define int long long

/* cpp template {{{ */

/* short */
#define pb push_back
#define mp make_pair
#define Fi first
#define Se second
#define ALL(v) (v).begin(), (v).end()

/* REPmacro */
#define REPS(i, a, n) for (int i = (a); i < (n); ++i)
#define REP(i, n) REPS(i, 0, n)
#define RREP(i, n) REPS(i, 1, n + 1)
#define DEPS(i, a, n) for (int i = (a); i >= n; --i)
#define DEP(i, n) DEPS(i, n, 0)

/* typedef */
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int> > vii;
typedef pair<int, int> pii;

/* const */
const int INF = 999999999;
const double EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool inside(int y, int x, int H, int W) {return y >= 0 && x >= 0 && y < H && x < W;}
inline int in() {int x; std::cin >> x; return x;}
template <typename T>
void print(std::vector<T>& v, char c = ' ') {
  REP(i, v.size()) {
    if (i != 0) std::cout << c;
    std::cout << v[i];
  }
  std::cout << '\n';
}
template <typename T>
void print(T x) {
  std::cout << x << '\n';
}

/* }}} */

typedef pair<double, double> P;

double cross(P& a, P& b) {
  return a.Fi * b.Se - a.Se * b.Fi;
}

P operator +(P& a, P& b) {
  return mp(a.Fi + b.Fi, a.Se + b.Se);
}
P operator -(P& a, P& b) {
  return mp(a.Fi - b.Fi, a.Se - b.Se);
}

signed main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  P n[3];
  P p;
  while (cin >> n[0].Fi >> n[0].Se) {
    REPS(i, 1, 3) cin >> n[i].Fi >> n[i].Se;
    cin >> p.Fi >> p.Se;
    bool flg = true;
    P v[] = {n[1] - n[0], n[2] - n[1], n[0] - n[2]};
    REP(i, 3) {
      P t = p - n[i];
      //print(cross(v[i], t));
      if (cross(v[i], t) < EPS) {
        print("NO");
        flg = false;
        break;
      }
    }
    if (flg) print("YES");
  }

  return 0;
}