import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)
##############################

class UnionFind:
    def __init__(self, N):
        self.rank = [0] * N
        self.parent = [i for i in range(N)]
        self.n = N

    def find(self, x):
        if self.parent[x] == x:
            return x
        else:
            self.parent[x] = self.find(self.parent[x])
            return self.parent[x]

    def unite(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if (x == y):
            return

        if (self.rank[x] < self.rank[y]):
            self.parent[x] = y
        else:
            self.parent[y] = x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def delete(self, idx):
        self.parent[idx] = -1

H, W = map(int, input().split())
uf = UnionFind(H*W+1)

pond = [ [0 for _ in range(W)] for _ in range(H) ]
idxs = [ [0 for _ in range(W)] for _ in range(H) ]

idx = 0
for i in range(H):
    A = list(map(int, input().split()))

    tmp_idx = []
    tmp = []
    for j in range(len(A)):
        tmp.append(A[j])
        tmp_idx.append(idx)

        idx += 1

    pond[i] = tmp
    idxs[i] = tmp_idx

#print(pond)
#print(idxs)
#exit()


for h in range(H):
    for w in range(W):
        if pond[h][w] == 0:
            # 対象外のは -1 を突っ込んで壊す
            uf.delete(idxs[h][w])
            continue

        if h > 0:
            if pond[h-1][w] == 1:
                uf.unite(idxs[h-1][w], idxs[h][w])
        if w > 0:
            if pond[h][w-1] == 1:
                uf.unite(idxs[h][w-1], idxs[h][w])
        if w < W-1:
            if pond[h][w+1] == 1:
                uf.unite(idxs[h][w+1], idxs[h][w])
        if h < H-1:
            if pond[h+1][w] == 1:
                uf.unite(idxs[h+1][w], idxs[h][w])

#print(uf.parent)

count = 0
for i in range(H*W):
    if uf.parent == -1:
        continue

    if uf.find(i) == i:
        count += 1

if count == H*W:
    print(0 if pond[0][0] == 0 else 1)
else:
    print(count)