Given an integer `num`, return the number of steps to reduce it to zero.

In one step, if the current number is even, you have to divide it by `2`, otherwise, you have to subtract `1` from it.

Example 1:

    Input: num = 14
    Output: 6
    Explanation:
    Step 1) 14 is even; divide by 2 and obtain 7.
    Step 2) 7 is odd; subtract 1 and obtain 6.
    Step 3) 6 is even; divide by 2 and obtain 3.
    Step 4) 3 is odd; subtract 1 and obtain 2.
    Step 5) 2 is even; divide by 2 and obtain 1.
    Step 6) 1 is odd; subtract 1 and obtain 0.

Example 2:

    Input: num = 8
    Output: 4
    Explanation:
    Step 1) 8 is even; divide by 2 and obtain 4.
    Step 2) 4 is even; divide by 2 and obtain 2.
    Step 3) 2 is even; divide by 2 and obtain 1.
    Step 4) 1 is odd; subtract 1 and obtain 0.

Example 3:

    Input: num = 123
    Output: 12

Constraints:

- `0 <= num <= 106`