Score : $100$ points

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 $10^{-6}$.

2 3

1.2000000000

100 99

49.7487437186