#include <fstream>
#include <vector>
using namespace std;

#define NMax 100005
#define MMax 500005

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

int n,m;

vector<int> v[NMax],w[NMax],t[NMax];
bool viz[NMax];
int used[MMax];

void DFS(int x)
{
    viz[x] = true;
    for(int i=0;i<v[x].size();++i) if(!used[w[x][i]])
    {
        if(!viz[v[x][i]]) t[x][i] = 1;
        else t[x][i] = 2;

        used[w[x][i]] = t[x][i];

        if(!viz[v[x][i]]) DFS(v[x][i]);
    }
    else t[x][i] = used[w[x][i]];
}

void DFS2(int x)
{
    if(m-- > 0) g<<x<<" ";

    for(int i=0;i<v[x].size();++i) if(used[w[x][i]] && t[x][i] == 2)
    {
        used[w[x][i]] = false;
        return DFS2(v[x][i]);
    }

    for(int i=0;i<v[x].size();++i) if(used[w[x][i]])
    {
        used[w[x][i]] = false;
        return DFS2(v[x][i]);
    }
}

int main()
{
    int i,a,b;

    f>>n>>m;
    for(i=1;i<=m;++i)
    {
        f>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
        w[a].push_back(i);
        w[b].push_back(i);
        t[a].push_back(0);
        t[b].push_back(0);
    }

    DFS(1);
    DFS2(1);

    f.close();
    g.close();
    return 0;
}