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;
int dx8[8] = {1, -1, 0, 0, 1, 1, -1, -1};
int dy8[8] = {0, 0, 1, -1, 1, -1, 1, -1};
void file() {}
void fast() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
}
int main() {
  long long n, i, j, k;
  cin >> n;
  long long a[1000], b[1000], maxi = -1, mini, maxii;
  for (i = 0; i < n; i++) cin >> a[i] >> b[i];
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      mini = 1e18, maxii = -1e18;
      for (k = 0; k < n; k++) {
        if ((i == j) || (i == k) || (j == k)) continue;
        long long val =
            ((a[k] - a[i]) * (b[j] - b[i]) - (a[j] - a[i]) * (b[k] - b[i]));
        mini = min(mini, val);
        maxii = max(maxii, val);
      }
      if (i != j) maxi = max(maxi, maxii - mini);
    }
  }
  cout << setprecision(12) << fixed;
  cout << (double)maxi / 2 << endl;
}