An integer N (1 ≤ N ≤ 10000), representing some quantity or size.
An integer K (1 ≤ K ≤ 10000), representing some quantity or size.
An integer X (1 ≤ X ≤ 10000), representing some value.
An integer Y (1 ≤ Y ≤ 10000), representing some value where Y < X.

### Example Input:

```
15
3
10000
9000
```

### Function Signature:
Write a function f(N, K, X, Y) that takes in the input.
def f(N: int, K: int, X: int, Y: int):
    '''
    N: an integer
    K: an integer
    X: an integer
    Y: an integer
    '''