An ugly number is a positive integer whose prime factors are limited to `2`, `3`, and `5`.

Given an integer `n`, return the `nth` ugly number.

Example 1:

    Input: n = 10
    Output: 12
    Explanation: [1, 2, 3, 4, 5, 6, 8, 9, 10, 12] is the sequence of the first 10 ugly numbers.

Example 2:

    Input: n = 1
    Output: 1
    Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.

Constraints:

- `1 <= n <= 1690`