Count Sub Islands

class Solution(object):
    def countSubIslands(self, grid1, grid2):
        rows=len(grid1)
        cols=len(grid1[0])
        
        def dfs(row,col):
            if row<0 or row>=rows or col<0 or col>=cols or grid2[row][col]==0:
                return 
            grid2[row][col]=0
            dfs(row+1,col)
            dfs(row-1,col)
            dfs(row,col+1)
            dfs(row,col-1)
  
        for row in range(rows):
            for col in range(cols):
                if grid2[row][col]==1 and grid1[row][col]==0:
                    dfs(row,col)
				
        count=0
        for row in range(rows):
            for col in range(cols):
                if grid2[row][col]==1:
                    
                    dfs(row,col)
                    count+=1
        return count