1000. Number of Closed Islands

Given a grid where 0 is land and 1 is water, return the number of closed islands — groups of land (connected 4-directionally) that are completely surrounded by water and do not touch the grid border. The input is JSON {grid}.

Input: JSON {grid}.

Output: Integer — the number of closed islands.

Examples

Input: {"grid":[[1,1,1,1,1],[1,0,0,0,1],[1,0,1,0,1],[1,0,0,0,1],[1,1,1,1,1]]}
Output: 2
Explanation: Two enclosed land regions.

Input: {"grid":[[0]]}
Output: 0
Explanation: Border land is not closed.

Input: {"grid":[[1,1,1],[1,0,1],[1,1,1]]}
Output: 1
Explanation: One enclosed cell.

Constraints

• 1<=rows,cols<=100
• 0 land, 1 water

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