#include<bits/stdc++.h>
const int N = 10000000;
using namespace std;
int m[1000][1000],d[N],l[N],sum=1,n,x,y,cnt=0,max_int=0;
void dfs(int i)
{
	int cnt1;
	for(cnt1 = 1;cnt1 <= max_int;++cnt1)
	{
		if(m[i][cnt1] >= 1)
		{
			m[i][cnt1]--,m[cnt1][i]--;
			dfs(cnt1);
		}
	}
	l[++cnt]=i;
}
int main()
{
	cin >> n;
	for (int i = 1;i <= n;++i){
		cin >> x >> y;
		m[x][y]++,m[y][x]++;
		d[x]++,d[y]++;
		max_int = max(max_int,max(x,y));
	}
	for(int i = 1;i <= max_int;++i)
	{
		if(d[i]%2)
		{
			sum=i;
			break;
		} 
	}
	dfs(sum);
	for(int i = cnt ; i >= 1;i--){
		cout << l[i] << endl;
	}
}