#include<iostream>
#include<fstream>
#include<vector>
#define NMAX 100005
using namespace std;

ifstream f("sortaret.in");
ofstream g("sortaret.out");

int n,m,exterior[NMAX];
bool viz[NMAX];
vector<int> v[NMAX];

void citire()
{
    f>>n>>m;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        f>>x>>y;
        v[x].push_back(y);
        exterior[y]++;
    }
}

void dfs(int node)
{
    g<<node<<" ";
    for(int i=0;i<v[node].size();i++)
    {
        if(viz[v[node][i]] == false && exterior[v[node][i]] <= 1)
        {
            viz[v[node][i]] = true;
            dfs(v[node][i]);
        }
        exterior[v[node][i]]--;
    }
}

int main()
{
    citire();
    dfs(1);
}