Given an integer `n`, return the number of ways you can write `n` as the sum of consecutive positive integers.

Example 1:

    Input: n = 5
    Output: 2
    Explanation: 5 = 2 + 3

Example 2:

    Input: n = 9
    Output: 3
    Explanation: 9 = 4 + 5 = 2 + 3 + 4

Example 3:

    Input: n = 15
    Output: 4
    Explanation: 15 = 8 + 7 = 4 + 5 + 6 = 1 + 2 + 3 + 4 + 5

Constraints:

- `1 <= n <= 109`