#include <iostream>
#include <fstream>
#include <vector>
#include <list>
using namespace std;
ifstream f("ciclueuler.in");
ofstream g("ciclueuler.out");
vector <int> a[100001],sol;
list <int> Q;
int n,m;
void euler(int x)
{
    vector <int>::iterator it;
    Q.push_back(x);
    while(!Q.empty())
    {
        x=Q.front();
        if(a[x].empty())
        {
            Q.pop_front();
            sol.push_back(x);
        }
        else
        {
            int i=a[x].back();
            Q.push_front(i);
            a[x].pop_back();
            for(it=a[i].begin();it!=a[i].end();it++)
            {
                if(*it==x)
                {
                    a[i].erase(it);
                    break;
                }
            }
        }
    }
}
int main()
{
    int i,x,y;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    euler(1);
    for(i=0;i<sol.size()-1;i++)
        g<<sol[i]<<" ";
    return 0;
}