Problem: Iahub has drawn a set of n points in the cartesian plane which he calls "special points". A quadrilateral is a simple polygon without self-intersections with four sides (also called edges) and four vertices (also called corners). Please note that a quadrilateral doesn't have to be convex. A special quadrilateral is one which has all four vertices in the set of special points. Given the set of special points, please calculate the maximal area of a special quadrilateral. 

Input

The first line contains integer n (4 ≤ n ≤ 300). Each of the next n lines contains two integers: xi, yi ( - 1000 ≤ xi, yi ≤ 1000) — the cartesian coordinates of ith special point. It is guaranteed that no three points are on the same line. It is guaranteed that no two points coincide. 

Output

Output a single real number — the maximal area of a special quadrilateral. The answer will be considered correct if its absolute or relative error does't exceed 10 - 9.

Examples

Input

5
0 0
0 4
4 0
4 4
2 3


Output

16.000000

Note

In the test example we can choose first 4 points to be the vertices of the quadrilateral. They form a square by side 4, so the area is 4·4 = 16.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int N = 1000005;
long long modd = 998244353;
vector<bool> isprime(N);
vector<int> primes;
void seive() {
  isprime[0] = false;
  isprime[1] = false;
  for (int i = 2; i <= 1e6; i++) {
    isprime[i] = true;
  }
  for (int i = 2; i * i <= 1e6; i++) {
    if (isprime[i]) {
      for (int j = i * i; j <= 1e6; j += i) {
        isprime[j] = false;
      }
    }
  }
  for (int i = 2; i < 1e6; i++) {
    if (isprime[i]) {
      primes.push_back(i);
    }
  }
}
void Reverse_Matrix() {
  long long n;
  cin >> n;
  double ans = 0;
  cout << fixed << setprecision(10);
  vector<double> x(n), y(n);
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> y[i];
  }
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      double x1 = 0, y1 = 0;
      for (int k = 0; k < n; k++) {
        double area =
            x[i] * (y[j] - y[k]) + x[j] * (y[k] - y[i]) + x[k] * (y[i] - y[j]);
        if (area > 0) {
          x1 = max(x1, abs(area));
        } else if (area < 0) {
          y1 = max(y1, abs(area));
        }
      }
      if (x1 && y1) {
        ans = max(ans, x1 + y1);
      }
    }
  }
  cout << ans / 2 << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  int TEST = 1;
  while (TEST--) {
    Reverse_Matrix();
  }
}