An integer N (1 ≤ N ≤ 100), representing some quantity or size.
An integer K (1 ≤ K ≤ 10^5), representing another quantity or size.
A list of N integers A, where 1 ≤ A[i] ≤ K and A[i] < A[i+1] for all valid i.

### Example Input:
```
2
4
2 3
```

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