Mr.Avantgarde needs to make a cuboid. He has ‘L’ units of a thin cord and ‘A’ unit square of a sheet. He wants to use all the cord and sheet. Cord is to be used to make edges and sheet is to be used to cover all the surface area of the cuboid. What is the maximum possible capacity of any such cuboid than can be made?

Constraints :

1 = T = 25

1 = L = 2^15-1

1 = A = 2^14-1

INPUT:

The first line contains T, the number of test cases. Then t test cases follow.

Each test case contains two integers L and A in a line. You may assume that there always exists an optimal solution for the given input cases.

Output:

For each test case, print a real number that is the largest volume of the box that  Mr. Avantgarde  can make, rounded to two decimal places.

SAMPLE TEST CASE:

Input:

2

20 14

20 16

Output:

3.00

4.15

Output details:

First case:

the dimensions of the largest box may be 3, 1 and 1.

Second case:

the dimensions of the largest box may be 7/3, 4/3 and 4/3.

Note: It is guaranteed that given inputs will have a optimal solution.