An integer `x` is a good if after rotating each digit individually by 180 degrees, we get a valid number that is different from `x`. Each digit must be rotated - we cannot choose to leave it alone.

A number is valid if each digit remains a digit after rotation. For example:

- `0`, `1`, and `8` rotate to themselves,
- `2` and `5` rotate to each other (in this case they are rotated in a different direction, in other words, `2` or `5` gets mirrored),
- `6` and `9` rotate to each other, and
- the rest of the numbers do not rotate to any other number and become invalid.

Given an integer `n`, return the number of good integers in the range `[1, n]`.

Example 1:

    Input: n = 10
    Output: 4
    Explanation: There are four good numbers in the range [1, 10] : 2, 5, 6, 9.
    Note that 1 and 10 are not good numbers, since they remain unchanged after rotating.

Example 2:

    Input: n = 1
    Output: 0

Example 3:

    Input: n = 2
    Output: 1

Constraints:

- `1 <= n <= 104`