Another Expected Value Problem

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You are given a sequence $A$ consisting of $N$ positive integers. Let $f(S)$ be defined for a non-empty subsequence $S$ as follows: $f(S) = \frac{g}{l + 1} $ where $g$ is GCD of the elements of the subsequence $S$ and $l$ is the length of the subsequence $S$. Find the expected value of $f(S)$ if all the non-empty subsequences are equiprobable. ### Input - The first line of the input contains

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solution.cppC++17

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