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

count = 2
stack = []
for h in range(H):
    for w in range(W):
        if A[h][w] == 0:continue
        if A[h][w] == 1:
            A[h][w] = count
            count += 1
        if h + 1 < H and A[h+1][w] == 1:
            A[h+1][w] = A[h][w]
        if w + 1 < W and A[h][w+1] == 1:
            A[h][w+1] = A[h][w]
print(count-2)