#include <iostream>
#include <stdio.h>
#include <vector>
using namespace std;

int n,m;
int Inside[10011];
vector<int> Graph[10011];

int q[10011];
int qL=0;

vector<int> ans;

int main()
{
    freopen("lottery.in","r",stdin);
    freopen("lottery.out","w",stdout);

    int i;
    int uk=1;
    int a,b;

    m=1;
    scanf("%d",&n);

    for (i=1;i<=n;i++)
    {
        scanf("%d %d",&a,&b);

        if (a>m)
        m=a;
        if (b>m)
        m=b;

        Graph[a].push_back(b);
        Inside[b]++;
    }

    for (i=1;i<=m;i++)
    {
        if (Inside[i]==0)
        {
            qL++;
            q[qL]=i;
        }
    }

    while(uk<=qL)
    {
        ans.push_back(q[uk]);

        for (i=0;i<Graph[ q[uk] ].size();i++)
        {
            Inside[ Graph[ q[uk] ][i] ]--;

            if (Inside[ Graph[ q[uk] ][i] ]==0)
            {
                qL++;
                q[qL]=Graph[ q[uk] ][i];
            }
        }

        uk++;
    }

    for (i=0;i<ans.size();i++)
    {
        printf("%d",ans[i]);

        if (i!=(int)ans.size()-1)
        printf(" ");
    }
    printf("\n");

    return 0;
}