using namespace std;

int main() {
    ios::sync_with_stdio(false);
        cin.tie(nullptr);
            freopen("boom.in", "r", stdin);
                freopen("boom.out", "w", stdout);

                    int n, m;
                        cin >> n >> m;
                            vector<string> g(n);
                                for (int i = 0; i < n; ++i) cin >> g[i];

                                    vector<int> row(n), col(m);
                                        for (int i = 0; i < n; ++i) {
                                                for (int j = 0; j < m; ++j) {
                                                            if (g[i][j] == '1') {
                                                                            ++row[i];
                                                                                            ++col[j];
                                                                                                        }
                                                                                                                }
                                                                                                                    }

                                                                                                                        vector<int> rvis(n), cvis(m);
                                                                                                                            int ans = 0;
                                                                                                                                for (int i = 0; i < n; ++i) {
                                                                                                                                        for (int j = 0; j < m; ++j) {
                                                                                                                                                    if (g[i][j] != '1' || rvis[i] || cvis[j]) continue;
                                                                                                                                                                ++ans;
                                                                                                                                                                            queue<pair<int,int>> q;
                                                                                                                                                                                        q.push({i, j});
                                                                                                                                                                                                    rvis[i] = cvis[j] = 1;
                                                                                                                                                                                                                while (!q.empty()) {
                                                                                                                                                                                                                                auto [x, y] = q.front(); q.pop();
                                                                                                                                                                                                                                                for (int k = 0; k < m; ++k) {
                                                                                                                                                                                                                                                                    if (g[x][k] == '1' && !cvis[k]) {
                                                                                                                                                                                                                                                                                            cvis[k] = 1;
                                                                                                                                                                                                                                                                                                                    q.push({x, k});
                                                                                                                                                                                                                                                                                                                                        }
                                                                                                                                                                                                                                                                                                                                                        }
                                                                                                                                                                                                                                                                                                                                                                        for (int k = 0; k < n; ++k) {
                                                                                                                                                                                                                                                                                                                                                                                            if (g[k][y] == '1' && !rvis[k]) {
                                                                                                                                                                                                                                                                                                                                                                                                                    rvis[k] = 1;
                                                                                                                                                                                                                                                                                                                                                                                                                                            q.push({k, y});
                                                                                                                                                                                                                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            cout << ans << '\n';
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                return 0;
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                }