An integer N (1 ≤ N ≤ 18), representing some quantity or size.
A list of integers A of size N, where each integer is between 1 and 50.
A list of integers B of size N, where each integer is between 1 and 50.

### Example Input:

```
3
3 4 3
3 2 3
```

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