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

There exists an infinitely large two-dimensional grid of uncolored unit cells. You are given a positive integer n, indicating that you must do the following routine for n minutes:

At the first minute, color any arbitrary unit cell blue.
Every minute thereafter, color blue every uncolored cell that touches a blue cell.

Below is a pictorial representation of the state of the grid after minutes 1, 2, and 3.

Return the number of colored cells at the end of n minutes.
 
Please complete the following python code precisely:
```python
class Solution:
    def coloredCells(self, n: int) -> int:
```