You are given an integer `n` and an integer `start`.

Define an array `nums` where `nums[i] = start + 2 * i` (0-indexed) and `n == nums.length`.

Return the bitwise XOR of all elements of `nums`.

Example 1:

    Input: n = 5, start = 0
    Output: 8
    Explanation: Array nums is equal to [0, 2, 4, 6, 8] where (0 ^ 2 ^ 4 ^ 6 ^ 8) = 8.
    Where "^" corresponds to bitwise XOR operator.

Example 2:

    Input: n = 4, start = 3
    Output: 8
    Explanation: Array nums is equal to [3, 5, 7, 9] where (3 ^ 5 ^ 7 ^ 9) = 8.

Constraints:

- `1 <= n <= 1000`
- `0 <= start <= 1000`
- `n == nums.length`