AtCoder Beginner Contest 138
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Problem Statement
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Given is a sequence of $N$ integers $A_1, \ldots, A_N$.
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Find the (multiplicative) inverse of the sum of the inverses of these numbers, $\frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}$.
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Constraints
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$1 \leq N \leq 100$$1 \leq A_i \leq 1000$
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Input
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Input is given from Standard Input in the following format:
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N
A_1 A_2 \ldots A_N翻译中…
Output
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Print a decimal number (or an integer) representing the value of $\frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}$.
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Your output will be judged correct when its absolute or relative error from the judge's output is at most $10^{-5}$.
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样例
Input #1
2
10 30
Output #1
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.
Input #2
3
200 200 200
Output #2
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.
Input #3
1
1000
Output #3
1000
$\frac{1}{\frac{1}{1000}} = 1000$.
Printing `+1000.0` and so on will also be accepted.
题目信息
题面与样例版权归 AtCoder 及出题人所有；中文翻译由 AI 生成（CI 管线），如有出入请以原文为准。