An integer N (1 ≤ N ≤ 2 × 10^5), representing some quantity or size.
An integer X (-10^8 ≤ X ≤ 10^8), representing a value.
An integer D (-10^8 ≤ D ≤ 10^8), representing a difference.

### Example Input:

```
3
4
2
```

### Function Signature:
Write a function f(N, X, D) that takes in the input. 
def f(N: int, X: int, D: int): 
    ''' 
    N: an integer 
    X: an integer
    D: an integer
    '''