Given a string `n` representing an integer, return the closest integer (not including itself), which is a palindrome. If there is a tie, return the smaller one.

The closest is defined as the absolute difference minimized between two integers.

Example 1:

    Input: n = "123"
    Output: "121"

Example 2:

    Input: n = "1"
    Output: "0"
    Explanation: 0 and 2 are the closest palindromes but we return the smallest which is 0.

Constraints:

- `1 <= n.length <= 18`
- `n` consists of only digits.
- `n` does not have leading zeros.
- `n` is representing an integer in the range `[1, 1018 - 1]`.