#include <iostream>
#include <fstream>
#include <bitset>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
int r[500001];
vector <int>nd[100001];
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");
inline void afisare(int m)
{
    for(int i=m;i>=1;i--) fout<<r[i]<<" ";
}
inline void euler(int nod)
{
    for(vector <int>::iterator it=nd[nod].begin();it!=nd[nod].end();it++)
    {
        int p=*it;
        nd[nod].erase(it);
        it--;
        if(p!=nod) nd[p].erase(find(nd[p].begin(),nd[p].end(),nod));
        euler(p);
    }
    r[++r[0]]=nod;
}
int main()
{
    int n,m,x,i=1,y;
    fin>>n>>m;
    while(i<=m)
    {   fin>>x>>y;
        nd[x].push_back(y);
        if(x!=y) nd[y].push_back(x);
        i++;
    }
    euler(1);
    afisare(m);
}