#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
using ll = long long;
using vll = vector<ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvll = vector<vector<ll>>;
const ll inf = 1e16;
const ll md = 1000000007;

bool a[3005][3005];
int h,w;

void bfs(int i,int j){
  vector<pair<int,int>> stack;
  stack.emplace_back(i,j);
  while(stack.size()){
    i=stack.back().first;
    j=stack.back().second;
    stack.pop_back();
    rep(ij,2) rep(pm,2){
      int ni=i+(pm*2-1)*ij;
      int nj=j+(pm*2-1)*(1-ij);
      if(ni<0 || nj<0 || ni>=h || nj>=w) continue;
      if(a[ni][nj]==false) continue;
      a[ni][nj]=false;
      stack.emplace_back(ni,nj);
    }
  }
}

int main() {
  cin>>h>>w;
  rep(i,h) rep(j,w){
    int aij;
    cin>>aij;
    a[i][j]=(aij==1);
    }
  int ans=0;
  rep(i,h) rep(j,w){
    if(a[i][j]==false) continue;
    a[i][j]=false;
    bfs(i,j);
    ans++;
  }
  cout<<ans<<endl;
  return 0;
}