#include <iostream>
#include <vector>

using namespace std;

void depth_first_search_step(vector< vector< int > > &edge, int connected_top[], int act_connected_top, int top, bool visited[]){
    if(visited[top]==true)
       return;
    visited[top] = true;
    connected_top[top] = act_connected_top;
    for(int i = 0; i<edge[top].size(); i++){
    if(visited[edge[top][i]]==false)
        depth_first_search_step(edge, connected_top, act_connected_top, edge[top][i], visited);
    }
    return;
}

void depth_first_search(vector< vector< int > > &edge, int connected_top[], int act_connected_top, int top){
    bool visited[edge.size()];
    for(int i=0; i<edge.size(); i++)
        visited[i] = false;

    depth_first_search_step(edge, connected_top, act_connected_top, top, visited);
    return;
}


//zmieniłem nazwę tej funkcji to nie było test, tylko chyba check_graph
void test(){

    int set_numbers;
    vector< vector< int > > edge;
    vector< int > pom;

    cin >> set_numbers;

    for(int tmpEdges=0; tmpEdges<set_numbers; tmpEdges++){
    edge.clear();

    int edgesQuantity;
    cin >> edgesQuantity;

    for(int l=0; l<edgesQuantity; l++){
        int top1,top2;

        cin >> top1 >> top2;

        while(edge.size()<top1 || edge.size()<top2)
            edge.push_back(pom);

        edge[top1-1].push_back(top2-1);
        edge[top2-1].push_back(top1-1);
    }

    int connected_top[edge.size()-1];
    for(int i=0; i<edge.size(); i++)
        connected_top[i] = 0;

    int act_connected_top = 0;

    for(int i=0; i<edge.size(); i++){
        if(connected_top[i]==0){
            act_connected_top++;
            depth_first_search(edge, connected_top, act_connected_top, i);
        }
    }

    for(int i=0; i<edge.size(); i++){
        act_connected_top = connected_top[i];

        bool occurred = false;

        for(int j=0; j<i; j++){
            if(connected_top[j] == act_connected_top){
                occurred = true;
                break;
            }
        }

        if(!occurred) {
            if(tmpEdges!=0 && act_connected_top == 1)
                cout << endl << endl;
            else if(act_connected_top != 1)
                cout << endl;

            cout << connected_top[i] << ":";
            for(int j=i; j<edge.size(); j++){
                if(connected_top[j]==act_connected_top)
                    cout << " " << j+1;
            }
        }
    }
}

return;}

int main() {
 test();
    return 0;
}