#include <bits/stdc++.h>

using namespace std;

ifstream in("ciclueuler.in");
ofstream out("ciclueuler.out");

const int Nmax = 1e5 + 5;

vector <int> G[Nmax], ans;
int N,M;

void euler(int node)
{
    if(!G[node].empty())
    {
        int y = G[node].back();
        G[node].pop_back();
        for(vector<int>::iterator i = G[y].begin(); i != G[y].end(); ++i)
        {
            if(*i == node)
            {
                G[y].erase(i);
                break;
            }
        }
        euler(y);
    }
    ans.push_back(node);

}
int main()
{
    in >> N >> M;
    int x,y;
    while(M--)
    {
        in >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    euler(1);
    for(auto i : ans)
        out << i << " ";
    return 0;
}