#include<bits/stdc++.h>
using namespace std;
int n,x,y,c=0;
int a[50][50];
void dfs(int m){
	cout<<m<<" "<<endl;
	for(int i=1;i<=n;i++){
		if(a[m][i]==1){
		    a[m][i]=0;
			a[i][m]=0;
			dfs(i);
			break;		
		}
	}
	
}
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>x>>y;
		a[x][y]=1;
		a[y][x]=1;
		a[x][0]++;
		a[y][0]++;	
    }
    for(int i=1;i<=n;i++){
    	if(a[i][0]%2==1){
    		c=i;
    		break;
    	} 
    }
    if(c==0) dfs(1);
    else dfs(c);
    return 0;
}
/**************************************************************
	Problem: 2054
	User: fuhongyi
	Language: C++
	Result: Wrong Answer
****************************************************************/