### Input Description:

An integer A (1 ≤ A ≤ 3), representing some quantity.
An integer B (1 ≤ B ≤ 3), representing some quantity.

### Example Input:

```
3 1
```

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