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

const int N=100005;
vector<int> a[N];

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

inline int abs(int a)
{
    return a>0 ? a : -a;
}

void pop(vector<int>& v,int x)
{
    int i=0,step=1<<18;
    for (i=-1;step;step>>=1)
        if (i+step<v.size() && abs(v[i+step])<x)
            i+=step;
    i++;
    v[i]*=-1;
}

void euler(int x)
{
    vector<int>::iterator i;
    while (a[x].size())
    {
        for (i=a[x].end()-1;i!=a[x].begin() && *i<0;i--);
        if (*i<0)
            return;
        out<<x<<" ";
        pop(a[*i],x);
        int q=*i;
        a[x].erase(i,a[x].end());
        x=q;
    }
}

int main()
{
    int m,n,x,y;
    in>>n>>m;
    while (m--)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for (int i=1;i<=n;i++)
        sort(a[x].begin(),a[x].end());
    euler(1);
    out<<"\n";
    return 0;
}