ABCD

A reconnaissance unit has sent a new report. A weapon called ABCD, made of four infinitely long parallel rails A, B, C, and D with one component on each rail, has fallen into terrorists' hands.

If even one component is destroyed or removed from its rail, ABCD activates immediately and causes a major disaster. Fortunately, each component is very light and can be moved freely along its rail.

At the moment ABCD tries to activate, if the four components are exactly the four vertices of a rectangle, ABCD loses its function and self-destructs. The amount of radiation released during self-destruction is proportional to the area of that rectangle.

Given the distances between adjacent rails, determine whether ABCD can be made to self-destruct. If it can, find the minimum possible area of the rectangle.

The first line contains three positive real numbers p, q, and r, separated by spaces. Each value is at most 10000.

The values p, q, and r are the distances between rails A and B, B and C, and C and D, respectively. Each value is given with at most two digits after the decimal point.

If ABCD cannot be made to self-destruct, print 0.

Otherwise, print the minimum possible area of the rectangle formed by the four components at self-destruction, rounded to exactly four digits after the decimal point.