#include <iostream>#include <vector>#include <cstdio>using namespace std;vector<int>map[10005];int vis[1005];int dfs(int s, int t, int n, int tmp[]){	if(s == t)	{		cout<<"1";		for(int i = 1; i < n; i++)		{			cout<<" "<<tmp[i];		}		cout<<endl;		return 0;	}	for(int i = 0; i < map[s].size(); i++)	{		if(vis[map[s][i]])	continue;		vis[map[s][i]] = 1;		tmp[n] = map[s][i];			dfs(map[s][i], t, n+1, tmp);		vis[map[s][i]] = 0;	}}int main(){	freopen("in.txt","r",stdin);	int tmp[1005];    int x, y, n;    while(cin>>n)    {    	vis[1] = 1;    	while(cin>>x>>y && x && y)    	{    		map[x].push_back(y);    		map[y].push_back(x);    	}    	dfs(1, n, 1, tmp);    }    return 0;}