Given is a sequence of $N$ integers $A_1, \ldots, A_N$.

Find the (multiplicative) inverse of the sum of the inverses of these numbers, $\frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}$.

Input is given from Standard Input in the following format:

```
$N$
$A_1$ $A_2$ $\ldots$ $A_N$
```

Print a decimal number (or an integer) representing the value of $\frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}$.

Your output will be judged correct when its absolute or relative error from the judge's output is at most $10^{-5}$.

-   $1 \leq N \leq 100$
-   $1 \leq A_i \leq 1000$

7.5

$\frac{1}{\frac{1}{10} + \frac{1}{30}} = \frac{1}{\frac{4}{30}} = \frac{30}{4} = 7.5$.

Printing 7.50001, 7.49999, and so on will also be accepted.

66.66666666666667

$\frac{1}{\frac{1}{200} + \frac{1}{200} + \frac{1}{200}} = \frac{1}{\frac{3}{200}} = \frac{200}{3} = 66.6666...$.

Printing 6.66666e+1 and so on will also be accepted.

1000

$\frac{1}{\frac{1}{1000}} = 1000$.

Printing +1000.0 and so on will also be accepted.