#include <bits/stdc++.h> using namespace std; #define For(i, a, b) for(int i = (a); i < (b); i++) #define rep(i, n) For(i, 0, n) #define rFor(i, a, b) for(int i = (a); i >= (b); i--) #define ALL(v) (v).begin(), (v).end() #define rALL(v) (v).rbegin(), (v).rend() using lint = long long; using ld = long double; int INF = 2000000000; lint LINF = 1000000000000000000; struct Fraction { using lint = long long; private: lint gcd(lint a_, lint b_) { unsigned long long a = abs(a_), b = abs(b_); if (a == 0 || b == 0) { return (a == 0 ? b : a); } int x = __builtin_ctzll(a), y = __builtin_ctzll(b); a >>= x; b >>= y; while (a != b) { if (a < b) { swap(a, b); } a -= b; a >>= __builtin_ctzll(a); } return (a << min(x, y)); } void reduce() { if (p != 0) { lint g = gcd(abs(p), abs(q)); p /= g; q /= g; } else { q = 1; } } int comp(lint a, lint b, lint c, lint d) const { if (a == c && b == d) { return 0; } return (a * d < c * b ? -1 : 1); } public: lint p, q; Fraction() : p(0), q(1) {} Fraction(lint p_, lint q_) : p(p_), q(q_) { assert(q_ != 0); if (q < 0) { p = -p; q = -q; } reduce(); } Fraction(lint p_) : p(p_), q(1) {} Fraction &operator+=(const Fraction &a) { lint np = p * a.q + q * a.p; lint nq = q * a.q; *this = Fraction(np, nq); return *this; } Fraction &operator-=(const Fraction &a) { lint np = p * a.q - q * a.p; lint nq = q * a.q; *this = Fraction(np, nq); return *this; } Fraction &operator*=(const Fraction &a) { lint np = p * a.p; lint nq = q * a.q; *this = Fraction(np, nq); return *this; } Fraction &operator/=(const Fraction &a) { assert(a.p != 0); lint np = p * a.q; lint nq = q * a.p; *this = Fraction(np, nq); return *this; } Fraction operator+(const Fraction &a) { return Fraction(*this) += a; } Fraction operator-(const Fraction &a) { return Fraction(*this) -= a; } Fraction operator*(const Fraction &a) { return Fraction(*this) *= a; } Fraction operator/(const Fraction &a) { return Fraction(*this) /= a; } Fraction operator-() { p = -p; return *this; } bool operator==(const Fraction &a) const { return comp(p, q, a.p, a.q) == 0; } bool operator!=(const Fraction &a) const { return comp(p, q, a.p, a.q) != 0; } bool operator<(const Fraction &a) const { return comp(p, q, a.p, a.q) == -1; } bool operator>(const Fraction &a) const { return comp(p, q, a.p, a.q) == 1; } bool operator<=(const Fraction &a) const { return comp(p, q, a.p, a.q) <= 0; } bool operator>=(const Fraction &a) const { return comp(p, q, a.p, a.q) >= 0; } friend ostream &operator<<(ostream &os, Fraction a) { return os << a.p << "/" << a.q; } }; using F = Fraction; using Point = pair<lint, lint>; using Line = pair<F, F>; Line get_line(Point p, Point q) { auto [x1, y1] = p; auto [x2, y2] = q; if (x1 != x2) { F A = F((y1 - y2), (x1 - x2)); F B = F((y2 - y1), (x1 - x2)) * F(x1) + F(y1); return {A, B}; } else { return {F(x1), F(LINF)}; } } bool same_side(Point p, Point q, Line l) { auto [x1, y1] = p; auto [x2, y2] = q; auto [a, b] = l; if (b != F(LINF)) { F Y1 = a * F(x1) + b; F Y2 = a * F(x2) + b; if (Y1 > y1 && Y2 > y2) { return true; } if (Y1 < y1 && Y2 < y2) { return true; } return false; } else { lint x = a.p; if (x1 < x && x2 < x) { return true; } if (x1 > x && x2 > x) { return true; } return false; } } ld get_angle(Point p, Point q, Point r) { auto [x1, y1] = p; auto [x2, y2] = q; auto [x3, y3] = r; using Vector = pair<F, F>; Vector pq = {F(x2 - x1), F(y2 - y1)}; Vector pr = {F(x3 - x1), F(y3 - y1)}; F ipf = pq.first * pr.first + pq.second * pr.second; F len_pq2 = pq.first * pq.first + pq.second * pq.second; F len_pr2 = pr.first * pr.first + pr.second * pr.second; ld ip = ld(ipf.p) / ld(ipf.q); ld len_pq = sqrt(ld(len_pq2.p) / ld(len_pq2.q)); ld len_pr = sqrt(ld(len_pr2.p) / ld(len_pr2.q)); ld cosine = ip / len_pq / len_pr; return acos(cosine); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); vector<Point> ps(4); rep(i, 4) { cin >> ps[i].first >> ps[i].second; } vector<int> ind = {0, 1, 2, 3}; do { Point p = ps[ind[0]], q = ps[ind[1]], r = ps[ind[2]], s = ps[ind[3]]; Line l = get_line(r, s); if (same_side(p, q, l)) { if (get_angle(p, r, s) == get_angle(q, r, s)) { cout << "YES\n"; return 0; } } } while (next_permutation(ALL(ind))); cout << "NO\n"; }