An integer X (0 ≤ X ≤ 10^18), representing some quantity.
An integer Y (0 ≤ Y ≤ 10^18), representing some quantity.

### Example Input:

```
2 1
```

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