#include <bits/stdc++.h>
using namespace std;
const double Pi = acos(-1.0);
inline int cmp(double x, double y = 0, double tol = 1e-7) {
  return (x <= y + tol) ? (x + tol < y) ? -1 : 0 : 1;
}
struct point {
  double x, y;
  point(double x = 0, double y = 0) : x(x), y(y) {}
  point operator+(point q) { return point(x + q.x, y + q.y); }
  point operator-(point q) { return point(x - q.x, y - q.y); }
  point operator*(double t) { return point(x * t, y * t); }
  point operator/(double t) { return point(x / t, y / t); }
  double operator*(point q) { return x * q.x + y * q.y; }
  double operator%(point q) { return x * q.y - y * q.x; }
  double polar() { return ((y > -1e-7) ? atan2(y, x) : 2 * Pi + atan2(y, x)); }
  double mod() { return sqrt(x * x + y * y); }
  double mod2() { return (x * x + y * y); }
  point rotate(double t) {
    return point(x * cos(t) - y * sin(t), x * sin(t) + y * cos(t));
  }
  point rotate(double sin, double cos) {
    return point(x * cos - y * sin, x * sin + y * cos);
  }
  int cmp(point q) const {
    if (int t = ::cmp(x, q.x)) return t;
    return ::cmp(y, q.y);
  }
  bool operator==(point q) const { return cmp(q) == 0; }
  bool operator!=(point q) const { return cmp(q) != 0; }
  bool operator<(point q) const { return cmp(q) < 0; }
  static point pivot;
};
point point::pivot;
double abs(point p) { return hypot(p.x, p.y); }
double arg(point p) { return atan2(p.y, p.x); }
inline int ccw(point p, point q, point r) { return cmp((p - r) % (q - r)); }
point proj(point v, point u) { return u * ((u * v) / (u * u)); }
inline double angle(point p, point q, point r) {
  point u = p - q, v = r - q;
  return atan2(u % v, u * v);
}
bool between(point p, point q, point r) {
  return ccw(p, q, r) == 0 && cmp((p - q) * (r - q)) <= 0;
}
bool seg_intersect(point p, point q, point r, point s) {
  point A = q - p, B = s - r, C = r - p, D = s - q;
  int a = cmp(A % C) + 2 * cmp(A % D);
  int b = cmp(B % C) + 2 * cmp(B % D);
  if (a == 3 || a == -3 || b == 3 || b == -3) return false;
  if (a || b || p == r || p == s || q == r || q == s) return true;
  int t = (p < r) + (p < s) + (q < r) + (q < s);
  return t != 0 && t != 4;
}
double seg_distance(point p, point q, point r) {
  point A = r - q, B = r - p, C = q - p;
  double a = A * A, b = B * B, c = C * C;
  if (cmp(b, a + c) >= 0)
    return sqrt(a);
  else if (cmp(a, b + c) >= 0)
    return sqrt(b);
  else
    return fabs(A % B) / sqrt(c);
}
int in_poly(point p, vector<point>& T) {
  double a = 0;
  int N = T.size();
  for (int i = 0; i < N; i++) {
    if (between(T[i], p, T[(i + 1) % N])) return -1;
    a += angle(T[i], p, T[(i + 1) % N]);
  }
  return cmp(a) != 0;
}
bool radial_lt(point p, point q) {
  point P = p - point::pivot, Q = q - point::pivot;
  double R = P % Q;
  if (cmp(R)) return R > 0;
  return cmp(P * P, Q * Q) < 0;
}
vector<point> convex_hull(vector<point>& T) {
  int j = 0, k, n = T.size();
  vector<point> U(n);
  point::pivot = *min_element((T).begin(), (T).end());
  sort((T).begin(), (T).end(), radial_lt);
  for (k = n - 2; k >= 0 && ccw(T[0], T[n - 1], T[k]) == 0; k--)
    ;
  reverse((k + 1) + (T).begin(), (T).end());
  for (int i = 0; i < n; i++) {
    while (j > 1 && ccw(U[j - 1], U[j - 2], T[i]) >= 0) j--;
    U[j++] = T[i];
  }
  U.erase(j + (U).begin(), (U).end());
  return U;
}
point line_intersect(point p, point q, point r, point s) {
  point a = q - p, b = s - r, c = point(p % q, r % s);
  return point(point(a.x, b.x) % c, point(a.y, b.y) % c) / (a % b);
}
double poly_area(vector<point>& T) {
  double s = 0;
  int n = T.size();
  for (int i = 0; i < n; i++) s += T[i] % T[(i + 1) % n];
  return s / 2;
}
struct segment {
  point a, b;
  segment(point a = point(0, 0), point b = point(0, 0)) : a(a), b(b) {}
  void input() {
    cin >> a.x >> a.y >> b.x >> b.y;
    if (b < a) swap(a, b);
  }
  void output() {
    printf("a=(%.1f  %.1f)  b=(%.1f  %.1f)\n", a.x, a.y, b.x, b.y);
  }
  bool operator<(const segment& q) const {
    return a < q.a || (a == q.a && b < q.b);
  }
};
bool solve(segment s[4]) {
  if (s[0].a != s[1].a) return false;
  if (s[0].b != s[2].a) return false;
  if (s[1].b != s[3].a) return false;
  if (s[2].b != s[3].b) return false;
  if (cmp(s[0].a.x, s[0].b.x) != 0) return false;
  if (cmp(s[1].a.y, s[1].b.y) != 0) return false;
  if (cmp(s[2].a.y, s[2].b.y) != 0) return false;
  if (cmp(s[3].a.x, s[3].b.x) != 0) return false;
  if (s[0].a == s[0].b) return false;
  if (s[1].a == s[1].b) return false;
  return true;
}
int main() {
  segment s[4];
  for (int i = 0; i < 4; i++) {
    s[i].input();
  }
  sort(s, s + 4);
  printf("%s\n", (solve(s) ? "YES" : "NO"));
  return 0;
}
