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: $*x*_{*i*}$, $*y*_{*i*}$ $( - 1000 ≤ *x*_{*i*}, *y*_{*i*} ≤ 1000)$ — the cartesian coordinates of $*i*$th 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 $10^{ - 9}$.

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 $4·4 = 16$.