음료수 얼려먹기 나의 답안

n, m = map(int, input().split())

ice =   [[0]*m for _ in range(n)]
visit = [[0]*m for _ in range(n)]
result = 0


def dfs(x, y):
    dirs = [(-1,0), (0, -1), (1, 0), (0, 1)]
    
    visit[y][x] = 1
    
    for dir in dirs:
        xd = x + dir[0]
        yd = y + dir[1]
        if xd>=0 and xd<m and yd >=0 and yd <n:
            if visit[yd][xd] == 0 and ice[yd][xd] == 0:
                dfs(xd, yd)

for i in range(n):
    str1 = input()
    for j in range(len(str1)):
        ice[i][j] = int(str1[j])

for i in range(n):
    for j in range(m):
        if ice[i][j] == 0 and visit[i][j] == 0:
            result += 1
            dfs(j, i)
            
print(result)