//#pragma GCC optimize(2)
#include<bits/stdc++.h>
#define ps ' '
#define Edl '\n'
#define debug(x) cerr<<#x<<':'<<x<<'\n';
#define edl '\n'
#define cehh cerr<<'\n';
typedef long long ll;
using namespace std;
inline ll read(){ll x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9') {if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9') x=(x<<1)+(x<<3)+(ch^48),ch=getchar();return x*f;}
void wrint(ll x,short e){if(x<0){putchar('-');x=-x;}if(x>9){wrint(x/10,0);}putchar(x%10+'0');if(e==1){putchar('\n');}if(e==2){putchar(' ');}}//0:啥也不加  1:换行  2:空格
const ll N=1e3 +10,INF=0x7f7f7f7f7f7f7f7f;
struct node{
	int v,id;
}o;
vector<node> e[N];
ll n=0,m=0,k=0,ans=0,du[N],p1,p2,num;
bool vis[N];
bool operator <(const node &a,const node &b){
	return a.v<b.v;
}
bool operator >(const node &a,const node &b){
	return a.v>b.v;
}
void dfs(int u){
	wrint(u,1);
	for(auto i:e[u]){
		if(!vis[i.id]){
			vis[i.id]=1;
			dfs(i.v);
			break;
		}
	}
}
int main(){
//	freopen("123.in","r",stdin);
//	freopen("123.out","w",stdout);
	m=read();
	for(int i=1;i<=m;i++){
		int u=read(),v=read();
		o.id=i;
		o.v=u;
		e[v].push_back(o);
		o.v=v;
		e[u].push_back(o);
		du[u]++;
		du[v]++;
		n=max(n,1ll*max(u,v));
	}
	for(int i=1;i<=n;i++){//判断奇数度点的数量
		sort(e[i].begin(),e[i].end());
		if(du[i]%2){
			if(p1) p2=i;
			else p1=i;
		}
	}
	if(p1){
		dfs(p1);
	}else{
		dfs(1);
	}
//	fclose(stdin);
//	fclose(stdout);

	return 0;
}

rt,下下来数据之后发现少输出了几个点，哪位奆佬帮帮我qwq