#include <bits/stdc++.h>

using namespace std;

using T = int; 
using T2 = long long;
using T4 = __int128_t;
const T2 INF = 2e9;

struct Line { T a, b; T2 c; };

bool operator<(Line m, Line n) {
  auto half = [&](Line m) { 
    return m.b < 0 || m.b == 0 && m.a < 0; };
  return make_tuple(half(m), (T2)m.b * n.a) < 
    make_tuple(half(n), (T2)m.a * n.b);
}
tuple<T4, T4, T2> LineIntersection(Line m, Line n) {
  T2 d = (T2)m.a * n.b - (T2)m.b * n.a; // assert(d);
  T4 x = (T4)m.c * n.b - (T4)m.b * n.c; 
  T4 y = (T4)m.a * n.c - (T4)m.c * n.a;
  return {x, y, d};
}
Line LineFromPoints(T x1, T y1, T x2, T y2) {
  T a = y1 - y2, b = x2 - x1;
  T2 c = (T2)a * x1 + (T2)b * y1;
  return {a, b, c};
}
ostream& operator<<(ostream& out, Line l) {
  out << "Line " << l.a << " " << l.b << " " << -l.c;
  // out << "(" << l.a << " * x + " << l.b << " * y <= " << l.c << ")";
  return out;
}


struct HalfplaneSet : multiset<Line> {
  HalfplaneSet() {
    insert({+1, 0, INF}); insert({0, +1, INF});
    insert({-1, 0, INF}); insert({0, -1, INF});
  };
 
  auto adv(auto it, int z) { // z = {-1, +1}
    return (z == -1
      ? --(it == begin() ? end() : it) 
      : (++it == end() ? begin() : it));
  }
  bool chk(auto it) {
    Line l = *it, pl = *adv(it, -1), nl = *adv(it, +1);
    T4 x, y; T2 d; tie(x, y, d) = LineIntersection(pl, nl);
    // auto [x, y, d] = LineIntersection(pl, nl);
    T4 sat = l.a * x + l.b * y - (T4)l.c * d;
    if (d < 0 && sat < 0) return clear(), 0; // unsat
    if ((d > 0 && sat <= 0) || (d == 0 && sat < 0))
      return erase(it), 1;
    return 0;
  }
  void Cut(Line l) { // add ax + by <= c
    if (empty()) return;
    auto it = insert(l);
    if (chk(it)) return;
    for (int z : {-1, +1}) 
      while (size() && chk(adv(it, z)));
  }
  // double Maximize(T a, T b) { // max ax + by
  //   if (empty()) return -1/0.;
  //   auto it = lower_bound({a, b});
  //   if (it == end()) it = begin();
  //   auto [x, y, d] = LineIntersection(*adv(it, -1), *it);
  //   return (1.0 * a * x + 1.0 * b * y) / d;
  // }
  double Area() {
    double total = 0.;
    for (auto it = begin(); it != end(); ++it) {
      T4 x1, y1, x2, y2; T2 d1, d2;
      tie(x1, y1, d1) = LineIntersection(*adv(it, -1), *it);
      tie(x2, y2, d2) = LineIntersection(*it, *adv(it, +1));
      // auto [x1, y1, d1] = LineIntersection(*adv(it, -1), *it);
      // auto [x2, y2, d2] = LineIntersection(*it, *adv(it, +1));
      total += (1.0 * x1 * y2 - 1.0 * x2 * y1) / d1 / d2;
    }
    return total * 0.5;
  }
};

int main() {
  ifstream fin("camera.in");
  ofstream fout("camera.out");

  int n; fin >> n;

  vector<T> x(n), y(n);
  for (int i = 0; i < n; ++i) 
    fin >> x[i] >> y[i];
  /*
  cout << "Polygon(";
  for (int i = 0; i < n; ++i) {
    if (i != 0) cout << ",";
    cout << "(" << x[i] << "," << y[i] << ")";
  }
  cout << ")" << endl;
  */
  double ans = 0;
  for (int rev = 0; rev < 2; ++rev) {
    HalfplaneSet HS;
    for (int j = n - 1, i = 0; i < n; j = i++) {
      HS.Cut(LineFromPoints(x[j], y[j], x[i], y[i]));
      //HS.Dump();
    }
    /*
    if (HS.size()) {
      cerr << "FINAL\n";
      for (auto x : HS) cerr << x << "\n";
    }*/
    ans = max(ans, HS.Area());
    reverse(x.begin(), x.end()); 
    reverse(y.begin(), y.end());
  }
  fout << fixed << setprecision(2) << ans << endl;

  return 0;
}