Contest Duration: ~ (local time)
A - 合成抵抗 / Equivalent Resistance

Time Limit: 2 sec / Memory Limit: 256 MB

### 問題文

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

R_1R_2 が与えられるので R_3 を求めてください。

### 制約

• 1 \leq R_1, R_2 \leq 100
• R_1, R_2 は整数

### 入力

R_1 R_2


R_3 の値を出力せよ。

### 入力例 1

2 3


### 出力例 1

1.2000000000


### 入力例 2

100 99


### 出力例 2

49.7487437186


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}.

### Sample Input 1

2 3


### Sample Output 1

1.2000000000


### Sample Input 2

100 99


### Sample Output 2

49.7487437186