Given an integer n, return the number of trailing zeroes in n!.

Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1.

Example 1:

Input: n = 3
Output: 0 (3! = 6, no trailing zero)

Example 2:

Input: n = 5
Output: 1 (5! = 120, one trailing zero)

Example 3:

Input: n = 25
Output: 6

Constraints: 0 <= n <= 10^4