#include <fstream>
#include <vector>
#include <stack>
#define NMax 100005
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

int N,M;
vector<int> G[NMax],Sol;
stack <int> S;
void Read()
{
    fin>>N>>M;
    for(int i=1;i<=M;i++)
        {
            int x,y;
            fin>>x>>y;
            G[x].push_back(y);
            G[y].push_back(x);
        }
}

void Erase(int Nod1, int Nod2)
{
    G[Nod1].erase(G[Nod1].begin());
    for(int i = 0; i< (int) G[Nod2].size(); i++)
        if(G[Nod2][i]==Nod1)
            {
                G[Nod2].erase(G[Nod2].begin() + i);
                break;
            }
}

void Cycle(int Nod)
{
    while(G[Nod].size())
    {
        S.push(Nod);
        int Vecin = G[Nod][0];
        Erase(Nod,Vecin);
        Nod = Vecin;
    }

}

void Solve()
{
    int Nod = 1;

    do
    {
        Cycle(Nod);
        Nod = S.top(); S.pop();
        Sol.push_back(Nod);
    }
    while(!S.empty());
}

void Print()
{
    for(int i=0;i< (int) Sol.size(); i++)
        fout<<Sol[i]<<" ";
    fout<<"\n";
}

int main()
{
    Read();
    Solve();
    Print();
    return 0;
}