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

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

void vprint(vector<ll> A){
    ll L = A.size();
    FOR(i, 0, L){
        if(i) cout << ' ';
        cout << A[i];
    }
    cout << endl;
}

struct Point{
    ll x;
    ll y;
    Point(ll x, ll y): x(x), y(y) {}
    Point(){}
};

int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};

ll A[3010][3010];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll H, W; cin >> H >> W;

    FOR(i, 0, H){
        FOR(j, 0, W){
            cin >> A[i][j];
        }
    }

    queue<Point> que;
    ll count = 0;
    FOR(y, 0, H){
        FOR(x, 0, W){
            if(A[y][x]==1){
                count++;
                que.push(Point(x, y));
                A[y][x] = 0;
                while(!que.empty()){
                    auto po = que.front();
                    que.pop();

                    FOR(i, 0, 4){
                        ll tx = po.x + dx[i];
                        ll ty = po.y + dy[i];
                        if(0<=tx && tx<W && 0<=ty && ty<H && A[ty][tx]==1){
                            A[ty][tx]=0;
                            que.push(Point(tx, ty));
                        }
                    }
                }
            }
        }
    }
    p(count);
    
    return 0;
}