An integer N (1 ≤ N ≤ 200,000), representing some quantity or size.
A list of integers S of size N, where each integer is between 1 and 100,000.

### Example Input:

```
6
1 2 3 1 2 3
```

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