#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int h, w;
    cin >> h >> w;

    int a[h+2][w+2];
    rep(i,h+2){
        rep(j,w+2){
            if(i == 0 || i == h + 1 || j == 0 || j == w + 1){
                a[i][j] = 0;
            }else{
                cin >> a[i][j];
            }
        }
    }

    int ans = 2;
    int dx[4] = {-1, 1, 0, 0};
    int dy[4] = {0, 0, -1, 1};

    rep(i,h+2){
        rep(j,w+2){
            if(a[i][j] == 1){
                queue<P> que;
                a[i][j] = ans;
                que.push(P(i, j));
                while(que.size()){
                    int x = que.front().first;
                    int y = que.front().second;
                    que.pop();
                    rep(k,4){
                        if(a[x+dx[k]][y+dy[k]] == 1){
                            a[x+dx[k]][y+dy[k]] = ans;
                            que.push(P(x+dx[k], y+dy[k]));
                        }
                    }
                }
                ans++;
            }
        }
    }

    ans -= 2;

    cout << ans << endl;
    return 0;
}