Problem: The night after the graduation ceremony graduate students of German University in Cairo (GUC) are playing darts. As there's no real dart board available, the photographs of members of the GUC upper management are being used.

So, n rectangular photos are placed on the wall. They can overlap arbitrary and even coincide. The photos are not necessarily placed horizontally or vertically, they could also be rotated before being pinned to the wall.

The score of one dart throw is simply the number of photos the dart went through.

Fatma has made a throw but her score was not recorded. She only remembers that she did make it into at least one photo.

Assuming that the probability distribution of the throw is equal across the whole wall, what would be the expectation of Fatma's score?

Input

The first line of input contains integer n (1 ≤ n ≤ 500) — the number of photos on the wall. Then follow n lines describing the photos, each containing 8 single-space-separated integers (coordinates of 4 vertices): x1, y1, x2, y2, x3, y3, x4, y4. Each photo is a rectangle with a nonzero area. The coordinates are integers, not exceeding 104 by absolute value. The coordinates of the rectangle are given in either clockwise or counterclockwise order.

Output

Print the expected score of the throw. The answer will be accepted if it has absolute or relative error not exceeding 10 - 6.

Examples

Input

1
0 0 0 2 2 2 2 0


Output

1.0000000000


Input

1
-1 0 0 1 1 0 0 -1


Output

1.0000000000


Input

4
0 0 0 1 3 1 3 0
0 0 0 3 1 3 1 0
3 3 2 3 2 0 3 0
3 3 3 2 0 2 0 3


Output

1.5000000000


Input

2
-1 0 0 1 1 0 0 -1
0 0 1 1 2 0 1 -1


Output

1.1428571429

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const double inf = 1e20;
const double pi = acos(-1.0);
const int maxp = 11;
int dblcmp(double d) {
  if (fabs(d) < eps) return 0;
  return d > eps ? 1 : -1;
}
inline double sqr(double x) { return x * x; }
struct point {
  double x, y;
  point() {}
  point(double _x, double _y) : x(_x), y(_y){};
  void input() { scanf("%lf%lf", &x, &y); }
  void output() { printf("%.2f %.2f\n", x, y); }
  bool operator==(point a) const {
    return dblcmp(a.x - x) == 0 && dblcmp(a.y - y) == 0;
  }
  bool operator<(point a) const {
    return dblcmp(a.x - x) == 0 ? dblcmp(y - a.y) < 0 : x < a.x;
  }
  double len() { return hypot(x, y); }
  double len2() { return x * x + y * y; }
  double distance(point p) { return hypot(x - p.x, y - p.y); }
  point add(point p) { return point(x + p.x, y + p.y); }
  point sub(point p) { return point(x - p.x, y - p.y); }
  point mul(double b) { return point(x * b, y * b); }
  point div(double b) { return point(x / b, y / b); }
  double dot(point p) { return x * p.x + y * p.y; }
  double det(point p) { return x * p.y - y * p.x; }
  double rad(point a, point b) {
    point p = *this;
    return fabs(atan2(fabs(a.sub(p).det(b.sub(p))), a.sub(p).dot(b.sub(p))));
  }
  point trunc(double r) {
    double l = len();
    if (!dblcmp(l)) return *this;
    r /= l;
    return point(x * r, y * r);
  }
  point rotleft() { return point(-y, x); }
  point rotright() { return point(y, -x); }
  point rotate(point p, double angle) {
    point v = this->sub(p);
    double c = cos(angle), s = sin(angle);
    return point(p.x + v.x * c - v.y * s, p.y + v.x * s + v.y * c);
  }
};
struct line {
  point a, b;
  line() {}
  line(point _a, point _b) {
    a = _a;
    b = _b;
  }
  bool operator==(line v) { return (a == v.a) && (b == v.b); }
  line(point p, double angle) {
    a = p;
    if (dblcmp(angle - pi / 2) == 0) {
      b = a.add(point(0, 1));
    } else {
      b = a.add(point(1, tan(angle)));
    }
  }
  line(double _a, double _b, double _c) {
    if (dblcmp(_a) == 0) {
      a = point(0, -_c / _b);
      b = point(1, -_c / _b);
    } else if (dblcmp(_b) == 0) {
      a = point(-_c / _a, 0);
      b = point(-_c / _a, 1);
    } else {
      a = point(0, -_c / _b);
      b = point(1, (-_c - _a) / _b);
    }
  }
  void input() {
    a.input();
    b.input();
  }
  void adjust() {
    if (b < a) swap(a, b);
  }
  double length() { return a.distance(b); }
  double angle() {
    double k = atan2(b.y - a.y, b.x - a.x);
    if (dblcmp(k) < 0) k += pi;
    if (dblcmp(k - pi) == 0) k -= pi;
    return k;
  }
  int relation(point p) {
    int c = dblcmp(p.sub(a).det(b.sub(a)));
    if (c < 0) return 1;
    if (c > 0) return 2;
    return 3;
  }
  bool pointonseg(point p) {
    return dblcmp(p.sub(a).det(b.sub(a))) == 0 &&
           dblcmp(p.sub(a).dot(p.sub(b))) <= 0;
  }
  bool parallel(line v) { return dblcmp(b.sub(a).det(v.b.sub(v.a))) == 0; }
  int segcrossseg(line v) {
    int d1 = dblcmp(b.sub(a).det(v.a.sub(a)));
    int d2 = dblcmp(b.sub(a).det(v.b.sub(a)));
    int d3 = dblcmp(v.b.sub(v.a).det(a.sub(v.a)));
    int d4 = dblcmp(v.b.sub(v.a).det(b.sub(v.a)));
    if ((d1 ^ d2) == -2 && (d3 ^ d4) == -2) return 2;
    return (d1 == 0 && dblcmp(v.a.sub(a).dot(v.a.sub(b))) <= 0 ||
            d2 == 0 && dblcmp(v.b.sub(a).dot(v.b.sub(b))) <= 0 ||
            d3 == 0 && dblcmp(a.sub(v.a).dot(a.sub(v.b))) <= 0 ||
            d4 == 0 && dblcmp(b.sub(v.a).dot(b.sub(v.b))) <= 0);
  }
  int linecrossseg(line v) {
    int d1 = dblcmp(b.sub(a).det(v.a.sub(a)));
    int d2 = dblcmp(b.sub(a).det(v.b.sub(a)));
    if ((d1 ^ d2) == -2) return 2;
    return (d1 == 0 || d2 == 0);
  }
  int linecrossline(line v) {
    if ((*this).parallel(v)) {
      return v.relation(a) == 3;
    }
    return 2;
  }
  point crosspoint(line v) {
    double a1 = v.b.sub(v.a).det(a.sub(v.a));
    double a2 = v.b.sub(v.a).det(b.sub(v.a));
    return point((a.x * a2 - b.x * a1) / (a2 - a1),
                 (a.y * a2 - b.y * a1) / (a2 - a1));
  }
  double dispointtoline(point p) {
    return fabs(p.sub(a).det(b.sub(a))) / length();
  }
  double dispointtoseg(point p) {
    if (dblcmp(p.sub(b).dot(a.sub(b))) < 0 ||
        dblcmp(p.sub(a).dot(b.sub(a))) < 0) {
      return min(p.distance(a), p.distance(b));
    }
    return dispointtoline(p);
  }
  point lineprog(point p) {
    return a.add(b.sub(a).mul(b.sub(a).dot(p.sub(a)) / b.sub(a).len2()));
  }
  point symmetrypoint(point p) {
    point q = lineprog(p);
    return point(2 * q.x - p.x, 2 * q.y - p.y);
  }
};
struct circle {
  point p;
  double r;
  circle() {}
  circle(point _p, double _r) : p(_p), r(_r){};
  circle(double x, double y, double _r) : p(point(x, y)), r(_r){};
  circle(point a, point b, point c) {
    p = line(a.add(b).div(2), a.add(b).div(2).add(b.sub(a).rotleft()))
            .crosspoint(
                line(c.add(b).div(2), c.add(b).div(2).add(b.sub(c).rotleft())));
    r = p.distance(a);
  }
  circle(point a, point b, point c, bool t) {
    line u, v;
    double m = atan2(b.y - a.y, b.x - a.x), n = atan2(c.y - a.y, c.x - a.x);
    u.a = a;
    u.b = u.a.add(point(cos((n + m) / 2), sin((n + m) / 2)));
    v.a = b;
    m = atan2(a.y - b.y, a.x - b.x), n = atan2(c.y - b.y, c.x - b.x);
    v.b = v.a.add(point(cos((n + m) / 2), sin((n + m) / 2)));
    p = u.crosspoint(v);
    r = line(a, b).dispointtoseg(p);
  }
  void input() {
    p.input();
    scanf("%lf", &r);
  }
  void output() { printf("%.2lf %.2lf %.2lf\n", p.x, p.y, r); }
  bool operator==(circle v) { return ((p == v.p) && dblcmp(r - v.r) == 0); }
  bool operator<(circle v) const {
    return ((p < v.p) || (p == v.p) && dblcmp(r - v.r) < 0);
  }
  double area() { return pi * sqr(r); }
  double circumference() { return 2 * pi * r; }
  int relation(point b) {
    double dst = b.distance(p);
    if (dblcmp(dst - r) < 0) return 2;
    if (dblcmp(dst - r) == 0) return 1;
    return 0;
  }
  int relationseg(line v) {
    double dst = v.dispointtoseg(p);
    if (dblcmp(dst - r) < 0) return 2;
    if (dblcmp(dst - r) == 0) return 1;
    return 0;
  }
  int relationline(line v) {
    double dst = v.dispointtoline(p);
    if (dblcmp(dst - r) < 0) return 2;
    if (dblcmp(dst - r) == 0) return 1;
    return 0;
  }
  int getcircle(point a, point b, double r, circle &c1, circle &c2) {
    circle x(a, r), y(b, r);
    int t = x.pointcrosscircle(y, c1.p, c2.p);
    if (!t) return 0;
    c1.r = c2.r = r;
    return t;
  }
  int getcircle(line u, point q, double r1, circle &c1, circle &c2) {
    double dis = u.dispointtoline(q);
    if (dblcmp(dis - r1 * 2) > 0) return 0;
    if (dblcmp(dis) == 0) {
      c1.p = q.add(u.b.sub(u.a).rotleft().trunc(r1));
      c2.p = q.add(u.b.sub(u.a).rotright().trunc(r1));
      c1.r = c2.r = r1;
      return 2;
    }
    line u1 = line(u.a.add(u.b.sub(u.a).rotleft().trunc(r1)),
                   u.b.add(u.b.sub(u.a).rotleft().trunc(r1)));
    line u2 = line(u.a.add(u.b.sub(u.a).rotright().trunc(r1)),
                   u.b.add(u.b.sub(u.a).rotright().trunc(r1)));
    circle cc = circle(q, r1);
    point p1, p2;
    if (!cc.pointcrossline(u1, p1, p2)) cc.pointcrossline(u2, p1, p2);
    c1 = circle(p1, r1);
    if (p1 == p2) {
      c2 = c1;
      return 1;
    }
    c2 = circle(p2, r1);
    return 2;
  }
  int getcircle(line u, line v, double r1, circle &c1, circle &c2, circle &c3,
                circle &c4) {
    if (u.parallel(v)) return 0;
    line u1 = line(u.a.add(u.b.sub(u.a).rotleft().trunc(r1)),
                   u.b.add(u.b.sub(u.a).rotleft().trunc(r1)));
    line u2 = line(u.a.add(u.b.sub(u.a).rotright().trunc(r1)),
                   u.b.add(u.b.sub(u.a).rotright().trunc(r1)));
    line v1 = line(v.a.add(v.b.sub(v.a).rotleft().trunc(r1)),
                   v.b.add(v.b.sub(v.a).rotleft().trunc(r1)));
    line v2 = line(v.a.add(v.b.sub(v.a).rotright().trunc(r1)),
                   v.b.add(v.b.sub(v.a).rotright().trunc(r1)));
    c1.r = c2.r = c3.r = c4.r = r1;
    c1.p = u1.crosspoint(v1);
    c2.p = u1.crosspoint(v2);
    c3.p = u2.crosspoint(v1);
    c4.p = u2.crosspoint(v2);
    return 4;
  }
  int getcircle(circle cx, circle cy, double r1, circle &c1, circle &c2) {
    circle x(cx.p, r1 + cx.r), y(cy.p, r1 + cy.r);
    int t = x.pointcrosscircle(y, c1.p, c2.p);
    if (!t) return 0;
    c1.r = c2.r = r1;
    return t;
  }
  int pointcrossline(line v, point &p1, point &p2) {
    if (!(*this).relationline(v)) return 0;
    point a = v.lineprog(p);
    double d = v.dispointtoline(p);
    d = sqrt(r * r - d * d);
    if (dblcmp(d) == 0) {
      p1 = a;
      p2 = a;
      return 1;
    }
    p1 = a.sub(v.b.sub(v.a).trunc(d));
    p2 = a.add(v.b.sub(v.a).trunc(d));
    return 2;
  }
  int relationcircle(circle v) {
    double d = p.distance(v.p);
    if (dblcmp(d - r - v.r) > 0) return 5;
    if (dblcmp(d - r - v.r) == 0) return 4;
    double l = fabs(r - v.r);
    if (dblcmp(d - r - v.r) < 0 && dblcmp(d - l) > 0) return 3;
    if (dblcmp(d - l) == 0) return 2;
    if (dblcmp(d - l) < 0) return 1;
  }
  int pointcrosscircle(circle v, point &p1, point &p2) {
    int rel = relationcircle(v);
    if (rel == 1 || rel == 5) return 0;
    double d = p.distance(v.p);
    double l = (d + (sqr(r) - sqr(v.r)) / d) / 2;
    double h = sqrt(sqr(r) - sqr(l));
    p1 = p.add(v.p.sub(p).trunc(l).add(v.p.sub(p).rotleft().trunc(h)));
    p2 = p.add(v.p.sub(p).trunc(l).add(v.p.sub(p).rotright().trunc(h)));
    if (rel == 2 || rel == 4) {
      return 1;
    }
    return 2;
  }
  int tangentline(point q, line &u, line &v) {
    int x = relation(q);
    if (x == 2) return 0;
    if (x == 1) {
      u = line(q, q.add(q.sub(p).rotleft()));
      v = u;
      return 1;
    }
    double d = p.distance(q);
    double l = sqr(r) / d;
    double h = sqrt(sqr(r) - sqr(l));
    u = line(q, p.add(q.sub(p).trunc(l).add(q.sub(p).rotleft().trunc(h))));
    v = line(q, p.add(q.sub(p).trunc(l).add(q.sub(p).rotright().trunc(h))));
    return 2;
  }
  double areacircle(circle v) {
    int rel = relationcircle(v);
    if (rel >= 4) return 0.0;
    if (rel <= 2) return min(area(), v.area());
    double d = p.distance(v.p);
    double hf = (r + v.r + d) / 2.0;
    double ss = 2 * sqrt(hf * (hf - r) * (hf - v.r) * (hf - d));
    double a1 = acos((r * r + d * d - v.r * v.r) / (2.0 * r * d));
    a1 = a1 * r * r;
    double a2 = acos((v.r * v.r + d * d - r * r) / (2.0 * v.r * d));
    a2 = a2 * v.r * v.r;
    return a1 + a2 - ss;
  }
  double areatriangle(point a, point b) {
    if (dblcmp(p.sub(a).det(p.sub(b)) == 0)) return 0.0;
    point q[5];
    int len = 0;
    q[len++] = a;
    line l(a, b);
    point p1, p2;
    if (pointcrossline(l, q[1], q[2]) == 2) {
      if (dblcmp(a.sub(q[1]).dot(b.sub(q[1]))) < 0) q[len++] = q[1];
      if (dblcmp(a.sub(q[2]).dot(b.sub(q[2]))) < 0) q[len++] = q[2];
    }
    q[len++] = b;
    if (len == 4 && (dblcmp(q[0].sub(q[1]).dot(q[2].sub(q[1]))) > 0))
      swap(q[1], q[2]);
    double res = 0;
    int i;
    for (i = 0; i < len - 1; i++) {
      if (relation(q[i]) == 0 || relation(q[i + 1]) == 0) {
        double arg = p.rad(q[i], q[i + 1]);
        res += r * r * arg / 2.0;
      } else {
        res += fabs(q[i].sub(p).det(q[i + 1].sub(p)) / 2.0);
      }
    }
    return res;
  }
};
struct polygon {
  int n;
  point p[maxp];
  line l[maxp];
  void input() {
    for (int i = 0; i < n; i++) {
      p[i].input();
    }
  }
  void add(point q) { p[n++] = q; }
  void getline() {
    for (int i = 0; i < n; i++) {
      l[i] = line(p[i], p[(i + 1) % n]);
    }
  }
  struct cmp {
    point p;
    cmp(const point &p0) { p = p0; }
    bool operator()(const point &aa, const point &bb) {
      point a = aa, b = bb;
      int d = dblcmp(a.sub(p).det(b.sub(p)));
      if (d == 0) {
        return dblcmp(a.distance(p) - b.distance(p)) < 0;
      }
      return d > 0;
    }
  };
  void norm() {
    point mi = p[0];
    for (int i = 1; i < n; i++) mi = min(mi, p[i]);
    sort(p, p + n, cmp(mi));
  }
  void getconvex(polygon &convex) {
    int i, j, k;
    sort(p, p + n);
    convex.n = n;
    for (i = 0; i < min(n, 2); i++) {
      convex.p[i] = p[i];
    }
    if (n <= 2) return;
    int &top = convex.n;
    top = 1;
    for (i = 2; i < n; i++) {
      while (top &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
    int temp = top;
    convex.p[++top] = p[n - 2];
    for (i = n - 3; i >= 0; i--) {
      while (top != temp &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
  }
  bool isconvex() {
    bool s[3];
    memset(s, 0, sizeof(s));
    int i, j, k;
    for (i = 0; i < n; i++) {
      j = (i + 1) % n;
      k = (j + 1) % n;
      s[dblcmp(p[j].sub(p[i]).det(p[k].sub(p[i]))) + 1] = 1;
      if (s[0] && s[2]) return 0;
    }
    return 1;
  }
  int relationpoint(point q) {
    int i, j;
    for (i = 0; i < n; i++) {
      if (p[i] == q) return 3;
    }
    getline();
    for (i = 0; i < n; i++) {
      if (l[i].pointonseg(q)) return 2;
    }
    int cnt = 0;
    for (i = 0; i < n; i++) {
      j = (i + 1) % n;
      int k = dblcmp(q.sub(p[j]).det(p[i].sub(p[j])));
      int u = dblcmp(p[i].y - q.y);
      int v = dblcmp(p[j].y - q.y);
      if (k > 0 && u < 0 && v >= 0) cnt++;
      if (k < 0 && v < 0 && u >= 0) cnt--;
    }
    return cnt != 0;
  }
  int relationline(line u) {
    int i, j, k = 0;
    getline();
    for (i = 0; i < n; i++) {
      if (l[i].segcrossseg(u) == 2) return 1;
      if (l[i].segcrossseg(u) == 1) k = 1;
    }
    if (!k) return 0;
    vector<point> vp;
    for (i = 0; i < n; i++) {
      if (l[i].segcrossseg(u)) {
        if (l[i].parallel(u)) {
          vp.push_back(u.a);
          vp.push_back(u.b);
          vp.push_back(l[i].a);
          vp.push_back(l[i].b);
          continue;
        }
        vp.push_back(l[i].crosspoint(u));
      }
    }
    sort(vp.begin(), vp.end());
    int sz = vp.size();
    for (i = 0; i < sz - 1; i++) {
      point mid = vp[i].add(vp[i + 1]).div(2);
      if (relationpoint(mid) == 1) return 1;
    }
    return 2;
  }
  void convexcut(line u, polygon &po) {
    int i, j, k;
    int &top = po.n;
    top = 0;
    for (i = 0; i < n; i++) {
      int d1 = dblcmp(p[i].sub(u.a).det(u.b.sub(u.a)));
      int d2 = dblcmp(p[(i + 1) % n].sub(u.a).det(u.b.sub(u.a)));
      if (d1 >= 0) po.p[top++] = p[i];
      if (d1 * d2 < 0) po.p[top++] = u.crosspoint(line(p[i], p[(i + 1) % n]));
    }
  }
  double getcircumference() {
    double sum = 0;
    int i;
    for (i = 0; i < n; i++) {
      sum += p[i].distance(p[(i + 1) % n]);
    }
    return sum;
  }
  double getarea() {
    double sum = 0;
    int i;
    for (i = 0; i < n; i++) {
      sum += p[i].det(p[(i + 1) % n]);
    }
    return fabs(sum) / 2;
  }
  bool getdir() {
    double sum = 0;
    int i;
    for (i = 0; i < n; i++) {
      sum += p[i].det(p[(i + 1) % n]);
    }
    if (dblcmp(sum) > 0) return 1;
    return 0;
  }
  point getbarycentre() {
    point ret(0, 0);
    double area = 0;
    int i;
    for (i = 1; i < n - 1; i++) {
      double tmp = p[i].sub(p[0]).det(p[i + 1].sub(p[0]));
      if (dblcmp(tmp) == 0) continue;
      area += tmp;
      ret.x += (p[0].x + p[i].x + p[i + 1].x) / 3 * tmp;
      ret.y += (p[0].y + p[i].y + p[i + 1].y) / 3 * tmp;
    }
    if (dblcmp(area)) ret = ret.div(area);
    return ret;
  }
  double areaintersection(polygon po) {}
  double areaunion(polygon po) {
    return getarea() + po.getarea() - areaintersection(po);
  }
  double areacircle(circle c) {
    int i, j, k, l, m;
    double ans = 0;
    for (i = 0; i < n; i++) {
      int j = (i + 1) % n;
      if (dblcmp(p[j].sub(c.p).det(p[i].sub(c.p))) >= 0) {
        ans += c.areatriangle(p[i], p[j]);
      } else {
        ans -= c.areatriangle(p[i], p[j]);
      }
    }
    return fabs(ans);
  }
  int relationcircle(circle c) {
    getline();
    int i, x = 2;
    if (relationpoint(c.p) != 1) return 0;
    for (i = 0; i < n; i++) {
      if (c.relationseg(l[i]) == 2) return 0;
      if (c.relationseg(l[i]) == 1) x = 1;
    }
    return x;
  }
  void find(int st, point tri[], circle &c) {
    if (!st) {
      c = circle(point(0, 0), -2);
    }
    if (st == 1) {
      c = circle(tri[0], 0);
    }
    if (st == 2) {
      c = circle(tri[0].add(tri[1]).div(2), tri[0].distance(tri[1]) / 2.0);
    }
    if (st == 3) {
      c = circle(tri[0], tri[1], tri[2]);
    }
  }
  void solve(int cur, int st, point tri[], circle &c) {
    find(st, tri, c);
    if (st == 3) return;
    int i;
    for (i = 0; i < cur; i++) {
      if (dblcmp(p[i].distance(c.p) - c.r) > 0) {
        tri[st] = p[i];
        solve(i, st + 1, tri, c);
      }
    }
  }
  circle mincircle() {
    random_shuffle(p, p + n);
    point tri[4];
    circle c;
    solve(n, 0, tri, c);
    return c;
  }
  int circlecover(double r) {
    int ans = 0, i, j;
    vector<pair<double, int> > v;
    for (i = 0; i < n; i++) {
      v.clear();
      for (j = 0; j < n; j++)
        if (i != j) {
          point q = p[i].sub(p[j]);
          double d = q.len();
          if (dblcmp(d - 2 * r) <= 0) {
            double arg = atan2(q.y, q.x);
            if (dblcmp(arg) < 0) arg += 2 * pi;
            double t = acos(d / (2 * r));
            v.push_back(make_pair(arg - t + 2 * pi, -1));
            v.push_back(make_pair(arg + t + 2 * pi, 1));
          }
        }
      sort(v.begin(), v.end());
      int cur = 0;
      for (j = 0; j < v.size(); j++) {
        if (v[j].second == -1)
          ++cur;
        else
          --cur;
        ans = max(ans, cur);
      }
    }
    return ans + 1;
  }
  int pointinpolygon(point q) {
    if (getdir()) reverse(p, p + n);
    if (dblcmp(q.sub(p[0]).det(p[n - 1].sub(p[0]))) == 0) {
      if (line(p[n - 1], p[0]).pointonseg(q)) return n - 1;
      return -1;
    }
    int low = 1, high = n - 2, mid;
    while (low <= high) {
      mid = (low + high) >> 1;
      if (dblcmp(q.sub(p[0]).det(p[mid].sub(p[0]))) >= 0 &&
          dblcmp(q.sub(p[0]).det(p[mid + 1].sub(p[0]))) < 0) {
        polygon c;
        c.p[0] = p[mid];
        c.p[1] = p[mid + 1];
        c.p[2] = p[0];
        c.n = 3;
        if (c.relationpoint(q)) return mid;
        return -1;
      }
      if (dblcmp(q.sub(p[0]).det(p[mid].sub(p[0]))) > 0) {
        low = mid + 1;
      } else {
        high = mid - 1;
      }
    }
    return -1;
  }
};
struct polygons {
  vector<polygon> p;
  polygons() { p.clear(); }
  void clear() { p.clear(); }
  void push(polygon q) {
    if (dblcmp(q.getarea())) p.push_back(q);
  }
  vector<pair<double, int> > e;
  void ins(point s, point t, point X, int i) {
    double r = fabs(t.x - s.x) > eps ? (X.x - s.x) / (t.x - s.x)
                                     : (X.y - s.y) / (t.y - s.y);
    r = min(r, 1.0);
    r = max(r, 0.0);
    e.push_back(make_pair(r, i));
  }
  double polyareaunion() {
    double ans = 0.0;
    int c0, c1, c2, i, j, k, w;
    for (i = 0; i < p.size(); i++) {
      if (p[i].getdir() == 0) reverse(p[i].p, p[i].p + p[i].n);
    }
    for (i = 0; i < p.size(); i++) {
      for (k = 0; k < p[i].n; k++) {
        point &s = p[i].p[k], &t = p[i].p[(k + 1) % p[i].n];
        if (!dblcmp(s.det(t))) continue;
        e.clear();
        e.push_back(make_pair(0.0, 1));
        e.push_back(make_pair(1.0, -1));
        for (j = 0; j < p.size(); j++)
          if (i != j) {
            for (w = 0; w < p[j].n; w++) {
              point a = p[j].p[w], b = p[j].p[(w + 1) % p[j].n],
                    c = p[j].p[(w - 1 + p[j].n) % p[j].n];
              c0 = dblcmp(t.sub(s).det(c.sub(s)));
              c1 = dblcmp(t.sub(s).det(a.sub(s)));
              c2 = dblcmp(t.sub(s).det(b.sub(s)));
              if (c1 * c2 < 0)
                ins(s, t, line(s, t).crosspoint(line(a, b)), -c2);
              else if (!c1 && c0 * c2 < 0)
                ins(s, t, a, -c2);
              else if (!c1 && !c2) {
                int c3 = dblcmp(t.sub(s).det(p[j].p[(w + 2) % p[j].n].sub(s)));
                int dp = dblcmp(t.sub(s).dot(b.sub(a)));
                if (dp && c0)
                  ins(s, t, a, dp > 0 ? c0 * ((j > i) ^ (c0 < 0)) : -(c0 < 0));
                if (dp && c3)
                  ins(s, t, b, dp > 0 ? -c3 * ((j > i) ^ (c3 < 0)) : c3 < 0);
              }
            }
          }
        sort(e.begin(), e.end());
        int ct = 0;
        double tot = 0.0, last;
        for (j = 0; j < e.size(); j++) {
          if (ct == 1) tot += e[j].first - last;
          ct += e[j].second;
          last = e[j].first;
        }
        ans += s.det(t) * tot;
      }
    }
    return fabs(ans) * 0.5;
  }
};
const int maxn = 500;
struct circles {
  circle c[maxn];
  double ans[maxn];
  double pre[maxn];
  int n;
  circles() {}
  void add(circle cc) { c[n++] = cc; }
  bool inner(circle x, circle y) {
    if (x.relationcircle(y) != 1) return 0;
    return dblcmp(x.r - y.r) <= 0 ? 1 : 0;
  }
  void init_or() {
    int i, j, k = 0;
    bool mark[maxn] = {0};
    for (i = 0; i < n; i++) {
      for (j = 0; j < n; j++)
        if (i != j && !mark[j]) {
          if ((c[i] == c[j]) || inner(c[i], c[j])) break;
        }
      if (j < n) mark[i] = 1;
    }
    for (i = 0; i < n; i++)
      if (!mark[i]) c[k++] = c[i];
    n = k;
  }
  void init_and() {
    int i, j, k = 0;
    bool mark[maxn] = {0};
    for (i = 0; i < n; i++) {
      for (j = 0; j < n; j++)
        if (i != j && !mark[j]) {
          if ((c[i] == c[j]) || inner(c[j], c[i])) break;
        }
      if (j < n) mark[i] = 1;
    }
    for (i = 0; i < n; i++)
      if (!mark[i]) c[k++] = c[i];
    n = k;
  }
  double areaarc(double th, double r) { return 0.5 * sqr(r) * (th - sin(th)); }
  void getarea() {
    int i, j, k;
    memset(ans, 0, sizeof(ans));
    vector<pair<double, int> > v;
    for (i = 0; i < n; i++) {
      v.clear();
      v.push_back(make_pair(-pi, 1));
      v.push_back(make_pair(pi, -1));
      for (j = 0; j < n; j++)
        if (i != j) {
          point q = c[j].p.sub(c[i].p);
          double ab = q.len(), ac = c[i].r, bc = c[j].r;
          if (dblcmp(ab + ac - bc) <= 0) {
            v.push_back(make_pair(-pi, 1));
            v.push_back(make_pair(pi, -1));
            continue;
          }
          if (dblcmp(ab + bc - ac) <= 0) continue;
          if (dblcmp(ab - ac - bc) > 0) continue;
          double th = atan2(q.y, q.x),
                 fai = acos((ac * ac + ab * ab - bc * bc) / (2.0 * ac * ab));
          double a0 = th - fai;
          if (dblcmp(a0 + pi) < 0) a0 += 2 * pi;
          double a1 = th + fai;
          if (dblcmp(a1 - pi) > 0) a1 -= 2 * pi;
          if (dblcmp(a0 - a1) > 0) {
            v.push_back(make_pair(a0, 1));
            v.push_back(make_pair(pi, -1));
            v.push_back(make_pair(-pi, 1));
            v.push_back(make_pair(a1, -1));
          } else {
            v.push_back(make_pair(a0, 1));
            v.push_back(make_pair(a1, -1));
          }
        }
      sort(v.begin(), v.end());
      int cur = 0;
      for (j = 0; j < v.size(); j++) {
        if (cur && dblcmp(v[j].first - pre[cur])) {
          ans[cur] += areaarc(v[j].first - pre[cur], c[i].r);
          ans[cur] +=
              0.5 * point(c[i].p.x + c[i].r * cos(pre[cur]),
                          c[i].p.y + c[i].r * sin(pre[cur]))
                        .det(point(c[i].p.x + c[i].r * cos(v[j].first),
                                   c[i].p.y + c[i].r * sin(v[j].first)));
        }
        cur += v[j].second;
        pre[cur] = v[j].first;
      }
    }
    for (i = 1; i <= n; i++) {
      ans[i] -= ans[i + 1];
    }
  }
};
struct halfplane : public line {
  double angle;
  halfplane() {}
  halfplane(point _a, point _b) {
    a = _a;
    b = _b;
  }
  halfplane(line v) {
    a = v.a;
    b = v.b;
  }
  void calcangle() { angle = atan2(b.y - a.y, b.x - a.x); }
  bool operator<(const halfplane &b) const { return angle < b.angle; }
};
struct halfplanes {
  int n;
  halfplane hp[maxp];
  point p[maxp];
  int que[maxp];
  int st, ed;
  void push(halfplane tmp) { hp[n++] = tmp; }
  void unique() {
    int m = 1, i;
    for (i = 1; i < n; i++) {
      if (dblcmp(hp[i].angle - hp[i - 1].angle))
        hp[m++] = hp[i];
      else if (dblcmp(
                   hp[m - 1].b.sub(hp[m - 1].a).det(hp[i].a.sub(hp[m - 1].a)) >
                   0))
        hp[m - 1] = hp[i];
    }
    n = m;
  }
  bool halfplaneinsert() {
    int i;
    for (i = 0; i < n; i++) hp[i].calcangle();
    sort(hp, hp + n);
    unique();
    que[st = 0] = 0;
    que[ed = 1] = 1;
    p[1] = hp[0].crosspoint(hp[1]);
    for (i = 2; i < n; i++) {
      while (st < ed &&
             dblcmp((hp[i].b.sub(hp[i].a).det(p[ed].sub(hp[i].a)))) < 0)
        ed--;
      while (st < ed &&
             dblcmp((hp[i].b.sub(hp[i].a).det(p[st + 1].sub(hp[i].a)))) < 0)
        st++;
      que[++ed] = i;
      if (hp[i].parallel(hp[que[ed - 1]])) return false;
      p[ed] = hp[i].crosspoint(hp[que[ed - 1]]);
    }
    while (
        st < ed &&
        dblcmp(hp[que[st]].b.sub(hp[que[st]].a).det(p[ed].sub(hp[que[st]].a))) <
            0)
      ed--;
    while (st < ed && dblcmp(hp[que[ed]]
                                 .b.sub(hp[que[ed]].a)
                                 .det(p[st + 1].sub(hp[que[ed]].a))) < 0)
      st++;
    if (st + 1 >= ed) return false;
    return true;
  }
  void getconvex(polygon &con) {
    p[st] = hp[que[st]].crosspoint(hp[que[ed]]);
    con.n = ed - st + 1;
    int j = st, i = 0;
    for (; j <= ed; i++, j++) {
      con.p[i] = p[j];
    }
  }
};
struct point3 {
  double x, y, z;
  point3() {}
  point3(double _x, double _y, double _z) : x(_x), y(_y), z(_z){};
  void input() { scanf("%lf%lf%lf", &x, &y, &z); }
  void output() { printf("%.2lf %.2lf %.2lf", x, y, z); }
  bool operator==(point3 a) {
    return dblcmp(a.x - x) == 0 && dblcmp(a.y - y) == 0 && dblcmp(a.z - z) == 0;
  }
  bool operator<(point3 a) const {
    return dblcmp(a.x - x) == 0
               ? dblcmp(y - a.y) == 0 ? dblcmp(z - a.z) < 0 : y < a.y
               : x < a.x;
  }
  double len() { return sqrt(len2()); }
  double len2() { return x * x + y * y + z * z; }
  double distance(point3 p) {
    return sqrt((p.x - x) * (p.x - x) + (p.y - y) * (p.y - y) +
                (p.z - z) * (p.z - z));
  }
  point3 add(point3 p) { return point3(x + p.x, y + p.y, z + p.z); }
  point3 sub(point3 p) { return point3(x - p.x, y - p.y, z - p.z); }
  point3 mul(double d) { return point3(x * d, y * d, z * d); }
  point3 div(double d) { return point3(x / d, y / d, z / d); }
  double dot(point3 p) { return x * p.x + y * p.y + z * p.z; }
  point3 det(point3 p) {
    return point3(y * p.z - p.y * z, p.x * z - x * p.z, x * p.y - p.x * y);
  }
  double rad(point3 a, point3 b) {
    point3 p = (*this);
    return acos(a.sub(p).dot(b.sub(p)) / (a.distance(p) * b.distance(p)));
  }
  point3 trunc(double r) {
    r /= len();
    return point3(x * r, y * r, z * r);
  }
  point3 rotate(point3 o, double r) {}
};
struct line3 {
  point3 a, b;
  line3() {}
  line3(point3 _a, point3 _b) {
    a = _a;
    b = _b;
  }
  bool operator==(line3 v) { return (a == v.a) && (b == v.b); }
  void input() {
    a.input();
    b.input();
  }
  double length() { return a.distance(b); }
  double dispointtoline(point3 p) {
    return b.sub(a).det(p.sub(a)).len() / a.distance(b);
  }
  double dispointtoseg(point3 p) {
    if (dblcmp(p.sub(b).dot(a.sub(b))) < 0 ||
        dblcmp(p.sub(a).dot(b.sub(a))) < 0) {
      return min(p.distance(a), p.distance(b));
    }
    return dispointtoline(p);
  }
  point3 lineprog(point3 p) {
    return a.add(b.sub(a).trunc(b.sub(a).dot(p.sub(a)) / b.distance(a)));
  }
  point3 rotate(point3 p, double ang) {
    if (dblcmp((p.sub(a).det(p.sub(b)).len())) == 0) return p;
    point3 f1 = b.sub(a).det(p.sub(a));
    point3 f2 = b.sub(a).det(f1);
    double len = fabs(a.sub(p).det(b.sub(p)).len() / a.distance(b));
    f1 = f1.trunc(len);
    f2 = f2.trunc(len);
    point3 h = p.add(f2);
    point3 pp = h.add(f1);
    return h.add((p.sub(h)).mul(cos(ang * 1.0)))
        .add((pp.sub(h)).mul(sin(ang * 1.0)));
  }
};
struct plane {
  point3 a, b, c, o;
  plane() {}
  plane(point3 _a, point3 _b, point3 _c) {
    a = _a;
    b = _b;
    c = _c;
    o = pvec();
  }
  plane(double _a, double _b, double _c, double _d) {
    o = point3(_a, _b, _c);
    if (dblcmp(_a) != 0) {
      a = point3((-_d - _c - _b) / _a, 1, 1);
    } else if (dblcmp(_b) != 0) {
      a = point3(1, (-_d - _c - _a) / _b, 1);
    } else if (dblcmp(_c) != 0) {
      a = point3(1, 1, (-_d - _a - _b) / _c);
    }
  }
  void input() {
    a.input();
    b.input();
    c.input();
    o = pvec();
  }
  point3 pvec() { return b.sub(a).det(c.sub(a)); }
  bool pointonplane(point3 p) { return dblcmp(p.sub(a).dot(o)) == 0; }
  double angleplane(plane f) {
    return acos(o.dot(f.o) / (o.len() * f.o.len()));
  }
  double dispoint(point3 p) { return fabs(p.sub(a).dot(o) / o.len()); }
  point3 pttoplane(point3 p) {
    line3 u = line3(p, p.add(o));
    crossline(u, p);
    return p;
  }
  int crossline(line3 u, point3 &p) {
    double x = o.dot(u.b.sub(a));
    double y = o.dot(u.a.sub(a));
    double d = x - y;
    if (dblcmp(fabs(d)) == 0) return 0;
    p = u.a.mul(x).sub(u.b.mul(y)).div(d);
    return 1;
  }
  int crossplane(plane f, line3 &u) {
    point3 oo = o.det(f.o);
    point3 v = o.det(oo);
    double d = fabs(f.o.dot(v));
    if (dblcmp(d) == 0) return 0;
    point3 q = a.add(v.mul(f.o.dot(f.a.sub(a)) / d));
    u = line3(q, q.add(oo));
    return 1;
  }
};
polygons ps;
int main() {
  int i, j, k;
  int n;
  scanf("%d", &n);
  double ans = 0;
  for (i = 0; i < n; i++) {
    polygon pl;
    pl.n = 4;
    pl.input();
    ans += pl.getarea();
    ps.push(pl);
  }
  printf("%.12lf\n", ans / ps.polyareaunion());
  return 0;
}