GEOMETRY

/*
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀       ⠀⠀⠀⠀⠀⠀⠀⣠⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀  ⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀     ⢀⣠⡯⠀⠀⠀⢠⡐⠀⠀⠀⠀⠀
⠀⠀⠀⢀⣤⠔⠂⠀⠀⠀⢤⣤⣤⣤⣄⣀⣀⣀⣀⡀⠀⢀⣀⣀⣀⡀⠀⠀⠀⢀⢀⣀⣠⣤⣴⣶⣾⠉⠉⠙⣶⠂⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀   ⠀⣰⣿⡟⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠰⣿⣷⣾⣿⣷⣴⣶⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠏⠉⠛⢿⣿⣿⣿⣿⣿⣿⣿⠿⠿⣿⣶⣿⣿⣿⣿⣤⣂⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣠⣤⣤⣤⣴⣦⣾⣿⣿⣿⣶⣦⣴⣶⣶⠀
⠀⠀⠀⣿⣿⣿⠿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣧⣤⣶⣶⣿⣿⣿⣿⣿⣿⣿⣯⣤⣤⣿⡿⠿⠿⠿⠛⠛⠛⠛⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣽⣿⣿⡟⢻⣿⣿⣿⡟⣿⣿⣿⣿⠉⠉⠁⠀
⠀⠀⠀⣹⣟⣿⣦⠈⠻⠋⢉⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⣿⣿⣿⣠⣾⣿⣿⣏⣤⣾⣿⣿⣿⡆⠀
⠀⠀⢀⣿⣿⣿⣿⣦⠀⠘⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⠟⢿⣿⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡧⠀
⠀⠀⢸⣿⣿⣿⣿⣿⡀⢀⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡈⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⡿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⠛⡄⠀
⠀⠀⠈⠿⠿⠁⣿⣿⣿⠎⠻⣯⠉⠉⠉⠈⠉⠉⠉⠉⠉⠉⠉⠉⠉⠉⢹⣿⢻⠉⠉⠁⠈⠻⢦⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⠁⠉⠙⠛⠛⢿⣿⠟⠋⠁⠀⠀⠀⠈⠀
⠀⠀⠀⠀⠀⠀⢹⣿⡟⠀⠀⠈⠳⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢿⠞⠀⠀⠀⠀⠀⠀⠙⠳⠤⠤⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀    ⠀⠀⠀⠁⠀⠀⠀⠀⠀⠸⣿⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⠀
⠀⠀⠀⠀⠀⠀⢈⡟⠇⠀⠀⠀⠀⠈⠁⠤⠤⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣶⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀     ⠀⠀⠀⢹⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠙⠀⠈⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠻⠂⠀⠀⠀⠀  ⠀⠀⠀⠀⠀⠀⠀⠀                             ⠀⠀⡘⡀⠀
⠀⠀⠀⠀⠀⠀                         ⠀⠀⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
*/

#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <memory.h>
#include <stdio.h>
#include <stack>
#include <deque>
#include <queue>
#include <set>
#include <iterator>
#include <map>
#include <iomanip>
#include <unordered_set>
#include <array>
#include <random>
#include <ctime>
#include <chrono>
#include <cstdlib>
//#define int long long
#define pb push_back
#define fir first
#define sec second
#define double long double
#define endl "\n"
#define un unsigned
#define INF 1000000000009
#define EPS 0.00000001
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;

const int N = 1000007, MOD = 1e9 + 7, R = 1 << 20, logn = 19, ABC = 26;
const double PI = acos(-1);

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

struct Point
{
    int x, y;

    Point(int a, int b) : x(a), y(b) {}
    Point() : x(0), y(0) {}
};

struct Vector
{
    Point a;

    Vector(Point a) : a(a) {}
    Vector(Point a, Point b) : a({ b.x - a.x, b.y - a.y }) {}
    Vector(int x, int y) : a({ x, y }) {}
    Vector(int x1, int y1, int x2, int y2) : a({ x2 - x1, y2 - y1 }) {}
};

istream& operator >> (istream& in, Point& a)
{
    in >> a.x >> a.y;
    return in;
}

int dot_product(Point a, Point b)
{
    return a.x * b.x + a.y * b.y;
}

int cross_product(Point a, Point b)
{
    return a.x * b.y - a.y * b.x;
}

double angle(Point a, Point b)
{
    double an = atan2(cross_product(a, b), dot_product(a, b));

    return abs(an);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout.precision(20);

    Point a, b, c, p;
    cin >> a >> b >> c >> p;

    Vector aa(b, a), bb(b, c), cc(b, p);

    double q = angle(aa.a, cc.a), w = angle(cc.a, bb.a), e = angle(aa.a, bb.a);

    if (abs(q + w - e) <= EPS)
    {
        cout << "YES";
    }
    else
    {
        cout << "NO";
    }

    return 0;
}