#include <fstream>
#include <vector>
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

vector<pair<int,int>> m;
vector<bool> fr;
vector<int> graf[500002],rez;
int i,n,muc,x,y;
void Euler(int start)
{
    for(auto x:graf[start])
    {
        if(fr[x]==0)
        {
            fr[x]=1;///vizitat
            int val=m[x].second;
            if(val==start)
                val=m[x].first;
            Euler(val);
        }
    }
    rez.push_back(start);
}


int main()
{
    fin>>n>>muc;
    for(i=1;i<=muc;i++)
    {
        fin>>x>>y;
        m.push_back(make_pair(x,y));
        fr.push_back(0);
        graf[x].push_back(m.size()-1);
        graf[y].push_back(m.size()-1);
    }
    Euler(1);
    for(i=0;i<rez.size()-1;i++)
        fout<<rez[i]<<' ';
    return 0;
}