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;
#pragma comment(linker, "/STACK:102400000,102400000")
const double eps = 1e-10;
struct Point {
  double x, y;
  Point(double x = 0, double y = 0) : x(x), y(y) {}
};
double dcmp(double x) {
  if (fabs(x) < eps) return 0;
  if (x > 0)
    return 1;
  else
    return -1;
}
Point operator+(Point a, Point b) { return Point(a.x + b.x, a.y + b.y); }
Point operator-(Point a, Point b) { return Point(a.x - b.x, a.y - b.y); }
Point operator*(Point a, double p) { return Point(a.x * p, a.y * p); }
bool operator==(Point a, Point b) {
  if (dcmp(a.x - b.x) == 0 && dcmp(a.y - b.y) == 0)
    return true;
  else
    return false;
}
struct Line {
  Point p;
  Point v;
  double ang;
  Line() {}
  Line(Point p, Point v) : p(p), v(v) {}
};
int n;
Point p[350];
Line line[90050];
double Dot(Point a, Point b) { return a.x * b.x + a.y * b.y; }
double Cross(Point a, Point b) { return a.x * b.y - a.y * b.x; }
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    p[i].x = x;
    p[i].y = y;
  }
  int cnt = 0;
  for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n; j++) line[cnt++] = Line(p[i], p[j] - p[i]);
  double ans = 0;
  for (int i = 0; i < cnt; i++) {
    double m1 = 0;
    double m2 = 0;
    for (int j = 0; j < n; j++) {
      double tmp = Cross(line[i].v, p[j] - line[i].p);
      if (tmp <= 0) {
        if (-tmp > m1) m1 = -tmp;
      } else {
        if (tmp > m2) m2 = tmp;
      }
    }
    if (m1 < eps || m2 < eps) continue;
    if ((m1 + m2) / 2.0 > ans) ans = (m1 + m2) / 2.0;
  }
  printf("%lf\n", ans);
}