class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

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

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

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

    def get_size(self, x):
        x = self.find(x)
        return self.size[x]
    
H, W = map(int, input().split())
U = UnionFind(H * W)
pre = [0] * W
cnt = 0
for i in range(H):
    L = list(map(int, input().split()))
    for j in range(W - 1):
        if L[j] and L[j + 1]:
            if U.is_same(i * W + j, i * W + j + 1):
                continue
            U.union(i * W + j, i * W + j + 1)
            cnt -= 1
    for j in range(W):
        if L[j]:
            cnt += 1
        if pre[j] and L[j]:
            if U.is_same((i - 1) * W + j, i * W + j):
                continue
            U.union((i - 1) * W + j, i * W + j)
            cnt -= 1
    L, pre = pre, L            
print(cnt)