Given an array `nums` of integers, we need to find the maximum possible sum of elements of the array such that it is divisible by three.

Example 1:

    Input: nums = [3,6,5,1,8]
    Output: 18
    Explanation: Pick numbers 3, 6, 1 and 8 their sum is 18 (maximum sum divisible by 3).

Example 2:

    Input: nums = [4]
    Output: 0
    Explanation: Since 4 is not divisible by 3, do not pick any number.

Example 3:

    Input: nums = [1,2,3,4,4]
    Output: 12
    Explanation: Pick numbers 1, 3, 4 and 4 their sum is 12 (maximum sum divisible by 3).

Constraints:

- `1 <= nums.length <= 4 * 10^4`
- `1 <= nums[i] <= 10^4`