Problem Statement

In an electric circuit, when two resistors ~R_1~ and ~R_2~ are connected in parallel, the equivalent resistance ~R_3~ can be derived from the following formula:

• ~\frac{1}{R_1} + \frac{1}{R_2} = \frac{1}{R_3}~

Given ~R_1~ and ~R_2~ , find ~R_3~ .

Constraints

• ~1 \leq R_1, R_2 \leq 100~
• ~R_1~ and ~R_2~ are integers.

Input

The input is given from Standard Input in the following format:

~R_1~ ~R_2~

Output

Print the value of ~R_3~ .

The output is considered correct if the absolute or relative error is at most ~10^{-6}~ .

Sample Input 1

2 3

Sample Output 1

1.2000000000

Sample Input 2

100 99

Sample Output 2

49.7487437186