#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> lpair;
const ll MOD = 1e9 + 7;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i = (m); i < (n); i++)
#define rrep(i,m,n) for(ll i = (m); i >= (n); i--)
#define print(x) cout << (x) << endl;
#define print2(x,y) cout << (x) << " " << (y) << endl;
#define printa(x,n) for(ll i = 0; i < n; i++){ cout << (x[i]) << " ";} cout<<endl;
bool check[3010][3010] = {};
int A[3010][3010] = {};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll H,W;
    cin >> H >> W;
    rep(i,0,H){
        rep(j,0,W){
            cin >> A[i][j];
        }
    }
    ll ans = 0;
    ll dx[4] = {0,0,1,-1};
    ll dy[4] = {1,-1,0,0};
    rep(h,0,H){
        rep(w,0,W){
            if(check[h][w] == 1 || A[h][w] == 0) continue;
            // print2(h,w);
            ans++;
            queue<lpair> q;
            q.push(make_pair(h,w));
            while(!q.empty()){
                lpair l1 = q.front();
                q.pop();
                if(check[l1.first][l1.second]) continue;
                check[l1.first][l1.second] = 1;
                rep(k,0,4){
                    ll hy = l1.first + dy[k];
                    ll wx = l1.second + dx[k];
                    
                    if(hy >= 0 && hy < H && wx >= 0 && wx < W){
                        
                        if(check[hy][wx] == 0 && A[hy][wx] == 1){
                            
                            q.push(make_pair(hy, wx));
                        }
                    }
                }

            }

        }
    }
    print(ans);
    
    
}