#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=int(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1e18;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

int h, w;
int a[3000][3000];

int main()
{
  cin >> h >> w;
  rep(i, h){
    rep(j, w){
      cin >> a[i][j];
    }
  }

  int ans = 0; 
  int dd[] = {1, 0, -1, 0, 1};
  rep(i, h) rep(j, w){
    if(a[i][j] == 1){
      ans++;
      queue<pii> que;
      que.push(mp(i, j));
      a[i][j] = 0;
      
      while(!que.empty()){
        pii p = que.front();
        que.pop();

        rep(i, 4){
          int nx = p.second + dd[i];
          int ny = p.first + dd[i+1];

          if(nx < 0 or w <= nx or ny < 0 or h <= ny) continue;
          if(a[ny][nx] == 1){
            que.push(mp(ny, nx));
            a[ny][nx] = 0;
          }
        }
      }
    }
  }
  
  cout << ans << endl;

  return 0;
}