from collections import deque
h, w = map(int, input().split())
grid = [list(input().split()) for _ in range(h)]

sensor = set()
q = deque()
visited = [[False for _ in range(w)] for _ in range(h)]
for j in range(h):
    for i in range(w):
        if grid[j][i] == '1':
            sensor.add((i, j))
count = 0
while sensor:
    q.append(sensor.pop())
    while q:
        x, y = q.popleft()
        if (x, y) in sensor:
            sensor.remove((x, y))
        
        for dx, dy in [(0, 1), (0, -1), (1, 0), (-1, 0)]:
            nx, ny = x + dx, y + dy
            if nx < 0 or w <= nx or ny < 0 or h <= ny:
                continue
            if grid[ny][nx] == '0':
                continue
            if not visited[ny][nx] and grid[ny][nx] == '1':
                visited[ny][nx] = True
                q.append((nx, ny))
                
    count += 1
print(count)