Expected Sum of Coins

You are given several test cases. In each test case, you are provided two integers N and M. Each test case represents a scenario where you have N coins. Each coin can have an integer value between 1 and M (inclusive), and every value is equally likely. Your task is to calculate the expected value of the sum of these coins.

The expected value for a single coin is given by the formula:

$$ E_{\text{coin}} = \frac{M+1}{2} $$

Thus, the expected sum for N coins is:

$$ E_{\text{total}} = N \times \frac{M+1}{2} $$

Output the result for each test case formatted to exactly two decimal places.

inputFormat

The first line of input contains a single integer T (T > 2), representing the number of test cases. Each of the following T lines contains two space-separated integers N and M.

outputFormat

For each test case, output the expected sum, printed on a new line. The result must be rounded and formatted to exactly two decimal places.

## sample

2
3 5
4 2

9.00
6.00

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