#include <bits/stdc++.h>
using namespace std;
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); }
  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) < (1e-10) && fabs(y - p.y) < (1e-10);
  }
};
class Segment {
 public:
  Point p1, p2;
  Segment(Point p1 = Point(0.0, 0.0), Point p2 = Point(0.0, 0.0))
      : p1(p1), p2(p2) {}
  double abs() { return sqrt(norm()); }
  double norm() {
    return (p2.x - p1.x) * (p2.x - p1.x) + (p2.y - p1.y) * (p2.y - p1.y);
  }
};
double norm(Point a) { return a.x * a.x + a.y * a.y; }
double abs(Point a) { return sqrt(norm(a)); }
Point polar(double a, double r) { return Point(cos(r) * a, sin(r) * a); }
double getDistance(Point a, Point b) { return abs(a - b); }
double dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }
double cross(Point a, Point b) { return a.x * b.y - a.y * b.x; }
bool isOrthogonal(Point a, Point b) {
  return (fabs((dot(a, b)) - (0.0)) < (1e-10));
}
bool isOrthogonal(Segment s1, Segment s2) {
  return (fabs((dot(s1.p2 - s1.p1, s2.p2 - s2.p1)) - (0.0)) < (1e-10));
}
bool isParallel(Point a, Point b) {
  return (fabs((cross(a, b)) - (0.0)) < (1e-10));
}
bool isParallel(Point a1, Point a2, Point b1, Point b2) {
  return isParallel(a1 - a2, b1 - b2);
}
bool isParallel(Segment s1, Segment s2) {
  return (fabs((cross(s1.p2 - s1.p1, s2.p2 - s2.p1)) - (0.0)) < (1e-10));
}
Point project(Segment s, Point p) {
  Point base = s.p2 - s.p1;
  double t = dot(p - s.p1, base) / norm(base);
  return s.p1 + base * t;
}
Point reflect(Segment s, Point p) { return p + (project(s, p) - p) * 2.0; }
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) {
  Point a = p1 - p0;
  Point b = p2 - p0;
  if (cross(a, b) > (1e-10)) return COUNTER_CLOCKWISE;
  if (cross(a, b) < -(1e-10)) return CLOCKWISE;
  if (dot(a, b) < -(1e-10)) return ONLINE_BACK;
  if (norm(a) < norm(b)) return ONLINE_FRONT;
  return ON_SEGMENT;
}
bool isIntersect(Point p1, Point p2, Point p3, Point p4) {
  return (ccw(p1, p2, p3) * ccw(p1, p2, p4) <= 0 &&
          ccw(p3, p4, p1) * ccw(p3, p4, p2) <= 0);
}
bool isIntersect(Segment s1, Segment s2) {
  return isIntersect(s1.p1, s1.p2, s2.p1, s2.p2);
}
Point getCrossPoint(Segment s1, Segment s2) {
  assert(isIntersect(s1, s2));
  Point base = s2.p2 - s2.p1;
  double d1 = abs(cross(base, s1.p1 - s2.p1));
  double d2 = abs(cross(base, s1.p1 - s2.p1));
  double t = d1 / (d1 + d2);
  return s1.p1 + (s1.p2 - s1.p1) * t;
}
double getDistanceLP(Segment s, Point p) {
  return abs(cross(s.p2 - s.p1, p - s.p1) / abs(s.p2 - s.p1));
}
double getDistanceSP(Segment s, Point p) {
  if (dot(s.p2 - s.p1, p - s.p1) < 0.0) return abs(p - s.p1);
  if (dot(s.p1 - s.p2, p - s.p2) < 0.0) return abs(p - s.p2);
  return getDistanceLP(s, p);
}
double getDistance(Segment s1, Segment s2) {
  if (isIntersect(s1, s2)) return 0.0;
  return min(min(getDistanceSP(s1, s2.p1), getDistanceSP(s1, s2.p2)),
             min(getDistanceSP(s2, s1.p1), getDistanceSP(s2, s1.p2)));
}
bool isConvex(Point P[4]) {
  int c = ccw(P[0], P[1], P[2]);
  for (int i = 1; i < 4; i++) {
    if (c != ccw(P[i], P[(i + 1) % 4], P[(i + 2) % 4])) return false;
  }
  return true;
}
bool isConvex(vector<Point> P) {
  int c = ccw(P[0], P[1], P[2]);
  for (int i = 1; i < 4; i++) {
    if (c != ccw(P[i], P[(i + 1) % 4], P[(i + 2) % 4])) return false;
  }
  return true;
}
vector<Point> andrewScan(vector<Point> s) {
  vector<Point> u, l;
  if (s.size() < 3) return s;
  sort(s.begin(), s.end());
  u.push_back(s[0]);
  u.push_back(s[1]);
  l.push_back(s[s.size() - 1]);
  l.push_back(s[s.size() - 2]);
  for (int i = 2; i < (int)s.size(); i++) {
    for (int n = u.size(); n >= 2 && ccw(l[n - 2], l[n - 1], s[i]) != CLOCKWISE;
         n--) {
      u.pop_back();
    }
    u.push_back(s[i]);
  }
  for (int i = s.size() - 3; i >= 0; i--) {
    for (int n = l.size(); n >= 2 && ccw(l[n - 2], l[n - 1], s[i]) != CLOCKWISE;
         n--) {
      l.pop_back();
    }
    l.push_back(s[i]);
  }
  reverse(l.begin(), l.end());
  for (int i = u.size() - 2; i >= 1; i--) l.push_back(u[i]);
  return l;
}
int main() {
  Point in;
  vector<Point> t;
  for (int i = 0; i < 4; i++) {
    cin >> in.x >> in.y;
    t.push_back(in);
  }
  cout << (isConvex(t) == true ? "YES" : "NO") << endl;
  return 0;
}
