B'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. The first line contains integer n (4 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89300). Each of the next n lines contains two integers: xi, yi ( xe2 x80 x89- xe2 x80 x891000 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89xi, xe2 x80 x89yi xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000) -- 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 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 xe2 x80 x89- xe2 x80 x899. 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 xc2 xb74 xe2 x80 x89= xe2 x80 x8916.'...