import sys
readline=sys.stdin.readline
from collections import defaultdict

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

    def Find(self,x):
        stack=[]
        while self.parents[x]>=0:
            stack.append(x)
            x=self.parents[x]
        for y in stack:
            self.parents[y]=x
        return 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):
        group_members = defaultdict(list)
        for member in range(self.n):
            group_members[self.Find(member)].append(member)
        return group_members

    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.All_Group_Members().items())

H,W=map(int,readline().split())
A=list(map(int,readline().split()))
ans=0
UF=UnionFind(H*W)
for w in range(W-1):
    if A[w] and A[w+1]:
        UF.Union(w,w+1)
ans-=A.count(0)
for h in range(1,H):
    prev=A
    A=list(map(int,readline().split()))
    for w in range(W-1):
        if A[w] and A[w+1]:
            UF.Union(h*W+w,h*W+w+1)
    for w in range(W):
        if prev[w] and A[w]:
            UF.Union((h-1)*W+w,h*W+w)
    ans-=A.count(0)
ans+=UF.Group_Count()
print(ans)