H, W = map(int, input().split())
A = [list(map(int, input().split())) for _ in range(H)]
group = [[0] * W for _ in range(H)]
def bfs(sr, sc, current_group, group, A, H, W):
    stack = [(sr, sc)]
    while stack:
        r, c = stack.pop()
        for dr, dc in zip([1, -1, 0, 0], [0, 0, 1, -1]):
            rr, cc = r + dr, c + dc
            if 0 <= rr < H and 0 <= cc < W:
                if group[rr][cc] or A[rr][cc] == 0:
                    continue
                group[rr][cc] = current_group
                stack.append((rr, cc))
ans = 0
for i in range(H):
    for j in range(W):
        if A[i][j] and group[i][j] == 0:
            ans += 1
            bfs(i, j, ans, group, A, H, W)
print(ans)