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

If the depth of a tree is smaller than 5, then this tree can be represented by an array of three-digit integers. You are given an ascending array nums consisting of three-digit integers representing a binary tree with a depth smaller than 5, where for each integer:

The hundreds digit represents the depth d of this node, where 1 <= d <= 4.
The tens digit represents the position p of this node within its level, where 1 <= p <= 8, corresponding to its position in a full binary tree.
The units digit represents the value v of this node, where 0 <= v <= 9.

Return the sum of all paths from the root towards the leaves.
It is guaranteed that the given array represents a valid connected binary tree.
 
Please complete the following python code precisely:
```python
class Solution:
    def pathSum(self, nums: List[int]) -> int:
```