// Name : Hemant Mangla

// username : hkmangla

// Country : India

// College : Deenbandhu Chhotu Ram University of Science and Technology Murthal

// emailId : [email protected]

#include "bits/stdc++.h"

using namespace std;

#define ll long long

#define pii pair<int,int>

#define pll pair<ll,ll>

#define rep(i,n) for(int i=0;i<n;i++)

#define repp(i,a,b) for(int i=a;i<b;i++)

#define MAXN 100005

vector<int> adj[100001];

vector<int> centroidTree[MAXN+1];

int centroidMarked[MAXN+1];

int setsubtreeSize(int s,bool vis[],int subtree[],int *n){

if(vis[s] or centroidMarked[s]) return 0;

vis[s] = true;

*n += 1;

subtree[s] = 1;

rep(i,adj[s].size()){

subtree[s] += setsubtreeSize(adj[s][i],vis,subtree,n);

}

return subtree[s];

}

int findCentroid(int s,int n,int subtree[],bool vis[]){

bool isCentroid = true;

vis[s] = true;

int hC = 0;

rep(i,adj[s].size()){

int e = adj[s][i];

if(!vis[e]){

if(subtree[e] > n/2) isCentroid = false;

if(hC == 0 || subtree[e] > subtree[hC]) hC = e;

}

}

if(isCentroid and subtree[s] > n/2) return s;

return findCentroid(hC,n,subtree,vis);

}

int getCentroid(int s){

bool vis[MAXN+1];

int subtree[MAXN+1];

memset(vis,false,sizeof(vis));

memset(subtree,0,sizeof(subtree));

int n = 0;

setsubtreeSize(s,vis,subtree,&n);

memset(vis,false,sizeof(vis));

int centroid = findCentroid(s,n,subtree,vis);

centroidMarked[centroid] = true;

return centroid;

}

int decomposeTree(int s){

int cent = getCentroid(s);

// cout<<cent<<" ";

rep(i,adj[cent].size()){

// cout<<adj[cent][i]<<" ";

if(!centroidMarked[adj[cent][i]]){

int cent_sub = decomposeTree(adj[cent][i]);

centroidTree[cent].push_back(cent_sub);

centroidTree[cent_sub].push_back(cent);

}

}

return cent;

}

int main(int argc, char const *argv[])

{

memset(centroidMarked,false,sizeof(centroidMarked));

int n; cin>>n;

rep(i,n-1){

int x,y; cin>>x>>y;

adj[x].push_back(y);

adj[y].push_back(x);

}

decomposeTree(1);

rep(i,n) {

cout<<i+1<<" ";

for(auto it:centroidTree[i+1]) cout<<it<<" ";

cout<<endl;

}

// cout<<endl;

return 0;

}