You are given an integer array coins representing available coin denominations and an integer k.

An amount is valid if it can be formed using a single denomination from coins (meaning the amount is a positive integer multiple of at least one element in coins).

Return the $k^{ ext{th}}$ smallest valid amount.

Constraints:

• $1 \leq$ coins.length $\leq 15$

• $1 \leq$ coins[i] $\leq 25$

• $1 \leq$ k $\leq 2 imes 10^9$

• coins contains pairwise distinct integers.

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