Given two integer X an N. Find real number Y such that Y¹ + Y² + Y³ + ... + Y^N = X. Your answer should be correct upto 9 decimal places.

Input
First line contains an integer T (number of test cases). Next T lines contains two integers separated by a single space denoting value of X and N respectively.

Output
For each testcase print answer upto exact 6 decimal places.
Number of decimal places should be exactly 6 else your solution will be judged as wrong answer.

Constraints
1 <= T <= 10³
1 <= X <= 10¹⁵
1 <= N <= 10³