Please solve the programming task below using a self-contained code snippet in a markdown code block.

You are given a 2D integer array coordinates and an integer k, where coordinates[i] = [xi, yi] are the coordinates of the ith point in a 2D plane.
We define the distance between two points (x1, y1) and (x2, y2) as (x1 XOR x2) + (y1 XOR y2) where XOR is the bitwise XOR operation.
Return the number of pairs (i, j) such that i < j and the distance between points i and j is equal to k.
 
Please complete the following python code precisely:
```python
class Solution:
    def countPairs(self, coordinates: List[List[int]], k: int) -> int:
```