from collections import deque

H, W = map(int, input().split())
A = tuple(tuple(map(int, input().split())) for _ in range(H))

directions = ((0, 1), (1, 0), (0, -1), (-1, 0))

visited = set()
ans = 0
for h in range(H):
    for w in range(W):
        if A[h][w] and (h, w) not in visited:
            ans += 1
            # dfs
            d = deque([(h, w)])
            while d:
                h, w = d.pop()
                visited.add((h, w))
                for dh, dw in directions:
                    hdh, wdw = h + dh, w + dw
                    if 0 <= hdh < H and 0 <= wdw < W and A[hdh][wdw] and (hdh, wdw) not in visited:
                        d.append((hdh, wdw))
print(ans)