Given a positive integer k, you need to find the length of the smallest positive integer n such that n is divisible by k, and n only contains the digit 1.
Return the length of n. If there is no such n, return -1.
Note: n may not fit in a 64-bit signed integer.
Example 1:
Input: k = 1 Output: 1 Explanation: The smallest answer is n = 1, which has length 1.
Example 2:
Input: k = 2 Output: -1 Explanation: There is no such positive integer n divisible by 2.
Example 3:
Input: k = 3 Output: 3 Explanation: The smallest answer is n = 111, which has length 3.
Constraints:
1 <= k <= 105