Given a positive integer n, return the smallest positive integer as a string such that the product of its digits is equal to n. If no such integer exists, return "-1".

Constraints:

• $1 \leq$ n $\leq 10^{18}$

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We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.