Given a positive integer N, find the smallest number S such that the product of all the digits of S is equal to the number N. If there's no such number, Print "-1".

Example 1:
Input:
N = 100
Output:
455
Explanation:
455 = 100. There are no numbers
less than 455 with the product of
it's digit as 100.
Example 2:
Input:
N = 26
Output:
-1
Explanation:
There are no numbers which can form
a product of 26 with its digits.

Your Task:
You don't need to read input or print anything. Your task is to complete the function getSmallest() which takes an Integer N as input and returns the answer as a String.

Expected Time Complexity: O(log(N))
Expected Auxiliary Space: O(1)

Constraints:
1 <= N <= 10^{9}

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