#include<bits/stdc++.h>
using namespace std;
const int N = 105;
vector<int>son[N];
vector<int>tr[N];
int n;
int de[N],lf[N];
int cnt;
void dfs(int u,int fa)
{
    for(auto v:tr[u]) if(v != fa && !lf[v]) dfs(v,u);
    for(auto v:son[u]) dfs(v,u);
    cout<<u<<" ";
}
void solve()
{
    cin>>n;cnt = 0;
    for(int i = 1;i <= n;i++) son[i].clear(),tr[i].clear();
    for(int i = 1,u,v;i < n;i++) 
    {
        cin>>u>>v;
        tr[u].push_back(v),tr[v].push_back(u);
    }
    for(int i = 1;i <= n;i++)
    {
        de[i] = tr[i].size();
        if(de[i] == n-1)
        {
            cout<<"2\n";
            for(int j = 1;j <= n;j++) if(i != j) cout<<j<<" ";
            cout<<i<<"\n";
            for(int j = n;j;j--) if(i != j) cout<<j<<" ";
            cout<<i<<"\n";
            return ;
        }
    }
    for(int i = 1;i <= n;i++)
    {
        if(tr[i].size() == 1) de[tr[i][0]]--,lf[i] = 1,son[tr[i][0]].push_back(i);
        else lf[i] = 0; 
    }
    for(int i = 1;i <= n;i++) if(de[i] == 1 && !lf[i]) cnt++;
    cout<<cnt<<"\n";
    for(int i = 1;i <= n;i++)
        if(de[i] == 1 && !lf[i])
        {
            dfs(i,0);
            cout<<"\n";
            for(int j = 1;j <= n;j++) reverse(son[j].begin(),son[j].end());
        }
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);
    int T;cin>>T;
    while(T--) solve();
    return 0;
}