An integer N (1 ≤ N ≤ 20), representing some quantity or size.
An integer A (1 ≤ A ≤ 50), representing some value or cost.
An integer B (1 ≤ B ≤ 50), representing another value or cost.

### Example Input:

```
4 2 9
```

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