Please solve the programming task below using a self-contained code snippet in a markdown code block.

You have n coins and you want to build a staircase with these coins. The staircase consists of k rows where the ith row has exactly i coins. The last row of the staircase may be incomplete.
Given the integer n, return the number of complete rows of the staircase you will build.
 
Please complete the following python code precisely:
```python
class Solution:
    def arrangeCoins(self, n: int) -> int:
```