#include <bits/stdc++.h>
#define MMAX 500009
#define NMAX 100009
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");
int uzm[MMAX];
int n,m;

struct muc{int y;int i;};
vector <muc>g[NMAX];
vector< int> C;
void citire();
void dfs(int k);
int main()
{citire();

    return 0;
}
void citire()
{
 int i;
 int x,y;
 fin>>n>>m;
 for(i=1;i<=m;i++)
    {fin>>x>>y;
     g[x].push_back({y,i});
     g[y].push_back({x,i});
    }
 dfs(1);
 for(i=C.size()-1;i>0;i--)
    fout<<C[i]<<" ";
}
void dfs(int k)
{
 int i;
 for(i=0;i<g[k].size();i++)
    if(!uzm[g[k][i].i])
    {
      uzm[g[k][i].i]=1;
      dfs(g[k][i].y);
    }
 C.push_back(k);
}