//#define _GLIBCXX_DEBUG #include #define rep(i, n) for(int i=0; i; using vs = vector; using vi = vector; using vvi = vector; template using PQ = priority_queue; template using PQG = priority_queue, greater >; const int INF = 100010001; const ll LINF = (ll)INF*INF*10; template inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);} template inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);} template istream &operator>>(istream &is, pair &p) { return is >> p.first >> p.second;} template ostream &operator<<(ostream &os, const pair &p) { return os << p.first << ' ' << p.second;} const double EPS = 1e-10; double add(double a, double b) { if(abs(a+b) < EPS*(abs(a)+abs(b))) return 0; return a+b; } struct Vector { double x, y; Vector(double x=0, double y=0):x(x), y(y) {} Vector const operator-() const {return Vector(-x, -y);} Vector operator+(Vector v) {return Vector(add(x, v.x), add(y, v.y));} Vector operator-(Vector v) {return Vector(add(x, -v.x), add(y, -v.y));} Vector operator*(double d) {return Vector(x*d, y*d);} Vector operator/(double d) {return Vector(x/d, y/d);} bool const operator!=(const Vector v) const {return abs(x-v.x)>EPS or abs(y-v.y)>EPS;} double dot(Vector v) {return add(x*v.x, y*v.y);} double cross(Vector v) {return add(x*v.y, -y*v.x);} Vector rotate(double theta) {return Vector(add(x*cos(theta), -y*sin(theta)), add(x*sin(theta), y*cos(theta)));} }; bool comps(Vector &a, Vector &b) { return a.cross(b) > 0; } const Vector origin = Vector(0, 0); struct Circle { Vector c; double r; Circle(Vector c=Vector(), double r=0):c(c), r(r) {} }; istream &operator>>(istream &is, Vector &v) {return is >> v.x >> v.y;} ostream &operator<<(ostream &os, const Vector &v) {return os << v.x << ' ' << v.y;} istream &operator>>(istream &is, Circle &c) {return is >> c.c >> c.r;} ostream &operator<<(ostream &os, const Circle &c) {return os << c.c << ' ' << c.r;} double sqdist(Vector v, Vector u) {return (v-u).dot(v-u);} //線分v2-v1上にあるか bool on_seg(Vector &v1,Vector &v2, const Vector &p) { return (v1-p).cross(v2-p) == 0 && (v1-p).dot(v2-p) <= 0; } //v1-v2とu1-u2の交点 Vector intersection(Vector &v1,Vector &v2,Vector &u1,Vector &u2) { assert((v1-v2).cross(u1-u2)); //2直線が平行だとだめ return v1 + (v2-v1)*((u2-u1).cross(u1-v1)/(u2-u1).cross(v2-v1)); } //p2-p1へのQの投影 Vector projection(Vector &p1,Vector &p2,Vector &Q) { return p1+(p2-p1)*(Q-p1).dot(p2-p1)/sqdist(p1, p2); } //p1-p2を軸としたQの線対称移動 Vector reflection(Vector &p1,Vector &p2,Vector &Q) { return projection(p1, p2, Q)*2-Q; } //2円が2点で交わりを持つか bool com_cir(Circle &a, Circle &b) { return add((a.r+b.r)*(a.r+b.r), - sqdist(a.c, b.c)) > 0; } //円aが円bを真に含んでいるか bool over_cir(Circle &a, Circle &b) { return add(a.r - sqrt(sqdist(a.c, b.c)), -b.r) > 0; } //円aが円bを含む&接している bool intouch_cir(Circle &a, Circle &b) { return add(a.r - sqrt(sqdist(a.c, b.c)), -b.r) == 0; } //円aが円bを含まない&接している bool outtouch_cir(Circle &a, Circle &b) { return add((a.r+b.r)*(a.r+b.r), - sqdist(a.c, b.c)) == 0; } //円aが真に含むか bool in_cir(Circle &a, Vector &p) { return add(sqdist(a.c, p), -a.r*a.r) < 0; } //円周上にあるか bool on_cir(Circle &a, Vector &p) { return add(sqdist(a.c, p), -a.r*a.r) == 0; } bool cmp_x(const Vector &v, const Vector &u) { if(v.x != u.x) return v.x < u.x; return v.y < u.y; } bool cmp_y(const Vector &v, const Vector &u) { if(v.y != u.y) return v.y < u.y; return v.x < u.x; } //凸包 頂点数nの頂点集合vv vector convex_hull(vector &vv, int n) { sort(vv.begin(), vv.end(), cmp_x); int k = 0; vector res(n*2); for(int i = 0; i < n; i++) { while(k > 1 && (res[k-1]-res[k-2]).cross(vv[i]-res[k-1]) <= 0) k--; res[k++] = vv[i]; } for(int i = n-2, t = k; i >= 0; i--) { while(k > t && (res[k-1]-res[k-2]).cross(vv[i]-res[k-1]) <= 0) k--; res[k++] = vv[i]; } res.resize(k-1); return res; } //点と線の距離 double distpl(Vector &p0, Vector &p1, Vector &Q) { Vector pp = projection(p0, p1, Q); return sqrt(sqdist(pp, Q)); } //線分と線分の距離 double distss(Vector &p0, Vector &p1, Vector &p2, Vector &p3) { if((p0-p1).cross(p2-p3) != 0) { Vector p = intersection(p0, p1, p2, p3); if(on_seg(p0, p1, p) and on_seg(p2, p3, p)) { return 0.0; } } double res = min({sqdist(p0, p2), sqdist(p0, p3), sqdist(p1, p2), sqdist(p1, p3)}); Vector pp0, pp1, pp2, pp3; pp2 = projection(p0, p1, p2); pp3 = projection(p0, p1, p3); pp0 = projection(p2, p3, p0); pp1 = projection(p2, p3, p1); if(on_seg(p0, p1, pp2)) res = min(res, sqdist(pp2, p2)); if(on_seg(p0, p1, pp3)) res = min(res, sqdist(pp3, p3)); if(on_seg(p2, p3, pp0)) res = min(res, sqdist(pp0, p0)); if(on_seg(p2, p3, pp1)) res = min(res, sqdist(pp1, p1)); res = sqrt(res); return res; } const int mod = 1000000007; //const int mod = 998244353; struct mint { int64_t x; mint(int64_t x=0):x((x%mod+mod)%mod){} mint operator-() const { return mint(-x);} mint& operator+=(const mint a) { if ((x += a.x) >= mod) x -= mod; return *this; } mint& operator-=(const mint a) { if ((x += mod-a.x) >= mod) x -= mod; return *this; } mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;} mint operator+(const mint a) const { return mint(*this) += a;} mint operator-(const mint a) const { return mint(*this) -= a;} mint operator*(const mint a) const { return mint(*this) *= a;} mint pow(int64_t t) const { if (!t) return 1; mint a = pow(t>>1); a *= a; if (t&1) a *= *this; return a; } //for prime mod mint inv() const { return pow(mod-2);} mint& operator/=(const mint a) { return *this *= a.inv();} mint operator/(const mint a) {return mint(*this) /= a;} }; istream& operator>>(istream& is, mint& a) { return is >> a.x;} ostream& operator<<(ostream& os, const mint& a) { return os << a.x;} //head int n; mint ans; vector xy; int main() { ios::sync_with_stdio(false); cin.tie(0); cin >> n; xy.resize(n); rep(i, n) cin >> xy[i]; rep(i, n) { //cout << endl; vector U; rep(j, n) if(xy[i] != xy[j]) { Vector t = xy[i]-xy[j]; if(t.y < 0) t = -t; U.emplace_back(t); } sort(all(U), comps); //rep(i, U.size()) cout << U[i] << endl; Vector X = origin; rep(j, U.size()) { ans += ll(X.cross(U[j])+0.1); X = X + U[j]; } } cout << ans/3 << endl; }