int main() {
    int n, m;
    cin >> n >> m;
    int countt = 0;
    for (int i = 0; i < m; i++) {
        int a1, a2;
        cin >> a1 >> a2;
        a[a1].push_back(a2);
        a[a2].push_back(a1);
    }
    //dfs(0, 1);
    for (int i = 1; i <= n; i++){
        if (users[i] == 0) {
        countt++;
            dfs(i, countt );
        }

    }

    cout << countt << "\n";
    int k = 1;
    for (int i = 1; i <= n; i++) cout << users[i] << " ";
    for (int i = 0; i < countt; i++) {
        for (int j = 0; i < n; i++) {
            if (users[j] == k) cout << j << " ";
        }
        cout << endl;
        k++;
    }
    return 0;
}