class Union_Find():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

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

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())
#-----------------------------------------------------------
H,W=map(int,input().split())
I=0
A=[]
D={}
L=[]

X=0
for i in range(H):
    F=list(map(int,input().split()))
    A.append(F)
    for j in range(W):
        if F[j]==1:
            D[I]=X
            X+=1
        I+=1

Z=Union_Find(X)

I=0
for y in range(H):
    for x in range(W):
        if x!=W-1:
            if A[y][x]==A[y][x+1]==1:
                J=y*W+x
                Q=D[J]
                Z.union(Q,Q+1)

        if y!=H-1:
            if A[y][x]==A[y+1][x]==1:
                J=y*W+x
                Z.union(D[J],D[J+W])            
            
print(Z.group_count())