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Rotated Digits

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.

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:

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 <= 10^4

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