An integer H (1 ≤ H ≤ 2×10^5), representing some quantity or size.
An integer W (1 ≤ W ≤ 2×10^5), representing some quantity or size.
An integer N (0 ≤ N ≤ 2×10^5), representing some quantity or size.
A list of tuples of size N, where each tuple (X_i, Y_i) contains two integers (1 ≤ X_i ≤ H, 1 ≤ Y_i ≤ W).

### Example Input:

```
3 3 1
3 2
```

### Function Signature:
Write a function f(H, W, N, obstacles) that takes in the input.
def f(H: int, W: int, N: int, obstacles: List[Tuple[int, int]]):
    ''' 
    H: an integer 
    W: an integer 
    N: an integer 
    obstacles: a list of tuples, each containing two integers 
    '''