#!/usr/bin/python3
"""Count the Manhattan-connected regions of 1s in a grid with flood fill."""

def grid1():
    return [[1, 0, 1],
            [1, 1, 0],
            [0, 0, 0],
            [1, 1, 1]]

def nuke(grid, house):
    stack = [house]
    while stack:
        x, y = stack.pop()
        #print(x, y)
        if not grid[y][x]:
            continue

        grid[y][x] = 0

        for nx in [x-1, x+1]:
            if 0 <= nx < len(grid[0]):
                stack.append((nx, y))

        for ny in [y-1, y+1]:
            if 0 <= ny < len(grid):
                stack.append((x, ny))
                    
def print_grid(grid):
    for row in grid:
        print(' '.join(map(str, row)))

def count_houses(grid):
    n = 0
    for y in range(len(grid)):
        for x in range(len(grid[0])):
            if not grid[y][x]:
                continue
            n += 1
            print_grid(grid)
            nuke(grid, (x, y))

    return n

if __name__ == '__main__':
    #import cgitb; cgitb.enable(format='text')
    grid = grid1()
    print(count_houses(grid))