An integer N (2 ≤ N ≤ 10^5), representing some quantity or size.
An integer L (1 ≤ L ≤ 10^9), representing some threshold.
A list of integers A of size N, where each integer is between 1 and 10^9.

### Example Input:
```
3 50
30 20 10
```

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