#include<iostream>
#include<vector>
#include<cstdio>
using namespace std;

long long x,y,a[10001],n,m;
vector <int> v[100001];

int main()
{
    freopen("lottery.in", "r", stdin);
	freopen("lottery.out", "w" , stdout);
    cin>>m;
    for(int i=1;i<=m;i++)
    {
        cin>>x>>y;
        n=max(n,max(x,y));
        v[x].push_back(y);
        a[y]++;
    }
    for(int i=1;i<=n;i++)
    if(a[i]==0){x=i;break;}
    cout<<x<<" ";
    for(int i=2;i<=n;i++)
    {
        for(int j=0;j<v[x].size();j++)
        {
            a[v[x][j]]--;
            if(a[v[x][j]]==0)y=v[x][j];
        }
        x=y;
        cout<<y<<" ";
    }
    return 0;
}