#include<bits/stdc++.h>
using namespace std;
int m,u,v,s[1010][1010],du[1010],cnt_ji,start = 0,cnt[1010],maxx = -999;
stack<int> sta;
void dfs(int x)
{
	for (int i = 1;i <= maxx;i++)
	{
		if (s[x][i])
		{
			s[x][i] = 0;
			s[i][x] = 0;
			dfs(i);
		}
	}
	sta.push(x);
}
int main()
{
	cin >> m;
	for (int i = 1;i <= m;i++)
	{
		cin >> u >> v;
		s[u][v] = 1;
		s[v][u] = 1;
		du[u]++;
		du[v]++;
		maxx = max(u,max(maxx,v));
	}
	for (int i = 1;i <= m;i++)
	{
		if (du[i] % 2 == 1)
		{
			cnt[cnt_ji] = i;
			cnt_ji++;
		}
	}
	if (cnt_ji == 2)
	{
		start = min(cnt[0],cnt[1]);
	}
	if(cnt_ji != 2)
	{
		for(int i = 1;i <= m;i++)
		{
			if(du[i])
			{
				start = i;
				break;
			}
		}
	}
	dfs(start);
	while(!sta.empty())
	{
		cout << sta.top() << endl;
		sta.pop();
	}
	/*
	for (int i = 1;i <= 4;i++)
	{
		for (int j = 1;j <= 4;j++)
		{
			cout << s[i][j] << ' ';
		}
		cout << endl;
	}
	*/
	return 0;
}
/*
#1的样例 
3
2 3
3 4
4 2

2
3
4
2
*/