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.
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.
For each test case output the answer in a single line.
Retain 1 digits after the decimal point.
3 1 1 -3 1 1 -9
1.9 7.8 0.0
Sichuan University Programming Contest 2011 Final