#include <fstream>
#include <vector>
#define NMax 100005
#define MMax 500005
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");
vector <int> g[NMax],c;
int n,m,a,b,i;
bool used[MMax];
int to[MMax],from[MMax];
void euler(int nod)
{
    while (!g[nod].empty())
    {
        int w=g[nod].back();
        g[nod].pop_back();
        if(!used[w])
        {
            used[w]=true;
            int next;
            if(from[w]==nod)
                next=to[w];
            else
                next=from[w];
            euler(next);
        }

    }
    c.push_back(nod);
}
int main()
{
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>a>>b;
        g[a].push_back(i);
        g[b].push_back(i);
        from[i]=a;
        to[i]=b;
    }
    euler(1);
    for(i=0; i<c.size()-1; i++)
        fout<<c[i]<<" ";
    return 0;
}