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Learning Opportunities

This puzzle can be solved using the following concepts. Practice using these concepts and improve your skills.

Statement

 Goal

You have an NxN grid consisting of white and black square pixels. White pixels are represented by . and black pixels are represented by #. The pixels on the outer edges of the grid are all white.

The black pixels form a single connected polygon without any holes (no group of white pixels is completely surrounded by black pixels).

How many sides does it have?

To be clear, the black area is a single region composed of one or more unit squares, and thus, all of its angles are 90 or 270 degree angles.
Input
Line 1: An integer N - the size of the grid
Next N lines: - the rows of the grid
Output
Line 1: The number of sides the black region has.
Constraints
- 3 ≤ N ≤ 10
- The pixels on the outer edge of the grid are all white.
- The black pixels form a single connected region.
- No group of white pixels is completely surrounded by black pixels.
Example
Input
4
....
.##.
.##.
....
Output
4

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