#P1198D. Rectangle Painting 1
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ID: 4320
Type: RemoteJudge
1000ms
256MiB
Tried: 1
Accepted: 1
Difficulty: 8
Uploaded By:
Hydro
Tags> Rectangle Painting 1
Description
There is a square grid of size . Some cells are colored in black, all others are colored in white. In one operation you can select some rectangle and color all its cells in white. It costs to color a rectangle of size . You are to make all cells white for minimum total cost.
The first line contains a single integer () — the size of the square grid.
Each of the next lines contains a string of length , consisting of characters '.' and '#'. The -th character of the -th line is '#' if the cell with coordinates is black, otherwise it is white.
Print a single integer — the minimum total cost to paint all cells in white.
Input
The first line contains a single integer () — the size of the square grid.
Each of the next lines contains a string of length , consisting of characters '.' and '#'. The -th character of the -th line is '#' if the cell with coordinates is black, otherwise it is white.
Output
Print a single integer — the minimum total cost to paint all cells in white.
Note
The examples and some of optimal solutions are shown on the pictures below.
