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

You are given a positive integer n. Each digit of n has a sign according to the following rules:

The most significant digit is assigned a positive sign.
Each other digit has an opposite sign to its adjacent digits.

Return the sum of all digits with their corresponding sign.
 
Please complete the following python code precisely:
```python
class Solution:
    def alternateDigitSum(self, n: int) -> int:
```