### Input Description:

1. An integer \( N \) (1 ≤ \( N \) ≤ 10^5), representing some quantity or size.
2. A list of \( N \) strings, where each string \( S_i \) (1 ≤ |\( S_i \)| ≤ 20) consists of uppercase letters of the alphabet.

### Example Input:

```
2
AORA
OR
```

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