DFS,BFS - 음료수 얼려먹기

n, m = map(int, input().split())
a = []
for i in range(n):
    a.append(list(map(int, input())))


def dfs(x, y):
    if x <= -1 or x >= n or y <= -1 or y >= m:  # 범위 지정 넘어가면
        return False  # False 반환
    if a[x][y] == 0:
        a[x][y] = 1
        dfs(x-1, y)
        dfs(x, y-1)
        dfs(x+1, y)
        dfs(x, y+1)
        return True
    return False


result = 0
for i in range(n):
    for j in range(m):
        if dfs(i, j) == True:
            result += 1

print(result)