#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;
int d[NMAX];
struct muc{int y;int i;};
queue <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({y,i});
     g[y].push({x,i});

    }
 dfs(1);
 for(i=C.size()-1;i>0;i--)
    fout<<C[i]<<" ";
}
void dfs(int k)
{
 int i,vec,ind;
 for(;!g[k].empty();)
    {vec=g[k].front().y;
     ind=g[k].front().i;
     g[k].pop();
     if(!uzm[ind])
         uzm[ind]=1,dfs(vec);

    }
 C.push_back(k);
}