#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");
vector < pair<int, int> >v[100005];
struct muchii
{
    int x, y;
}muchi[500005];
int rez[500005], w[500005], nr, grad[500005];
void dfs(int nod)
{

    for(int i=0; i<v[nod].size(); i++)
        if(w[v[nod][i].second]==0)
        {
            w[v[nod][i].second]=1;
            dfs(v[nod][i].first);
        }
    nr++;
    rez[nr]=nod;
}
int main()
{
    int n, m;
    fin >> n >> m;
    for(int i=1; i<=m; i++)
    {
        int x, y;
        fin >> x >> y;
        v[x].push_back(make_pair(y, i));
        v[y].push_back(make_pair(x, i));
    }
    dfs(1);
    for(int i=1; i<=nr; i++)
        fout << rez[i] << " ";


    //fout << rez[1];
    return 0;
}