Description

Given an unary quadratic function: F(x) = -x^2 + B * x + C, you are to calculate the area surrounded by x-axis and the part of the curve of F(x) above x-axis.

Input

The first line of the input is an integer T which stands for the number of test cases.
Then T test cases follow, and each test case contains one line with 2 integers B and C.

Constraints

|B| and |C| are in the range of [0, 10].

Output

For each test case output the answer in a single line.
Retain 1 digits after the decimal point.

Sample Input

3
1 1
-3 1
1 -9

Sample Output

1.9
7.8
0.0

Author

baihacker

Source

Sichuan University Programming Contest 2011 Final