from collections import deque
H, W = map(int, input().split())
A = [list(map(int, input().split())) for _ in range(H)]
def bfs(sr, sc, A, H, W):
    # 幅優先探索
    que = deque((sr, sc))
    while que:
        r, c = que.popleft()
        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 and A[rr][cc]:
                que.append((rr, cc))
                # 水を抜く
                A[rr][cc] = 0
ans = 0
for i in range(H):
    for j in range(W):
        if A[i][j]:
            ans += 1
            bfs(i, j, A, H, W)
print(ans)