#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++)

int H,W;

int A[3030][3030];

int main(){
  cin >> H >> W;
  rep(i,1,H){
    rep(j,1,W){
      cin >> A[i][j];
    }
  }

  using P = pair<int,int>;
  int ans = 0;

  rep(i,1,H){
    rep(j,1,W){
      if(A[i][j] == 0) continue;
      queue<P> que;
      que.push({i,j});
      while(!que.empty()){
        int x = que.front().first;
        int y = que.front().second;
        que.pop();
        if(A[x][y] == 0) continue;
        A[x][y] = 0;
        que.push({x + 1,y});
        que.push({x - 1,y});
        que.push({x,y + 1});
        que.push({x,y - 1});
      }
      ans++;
    }
  }

  cout << ans << endl;
}