#include <bits/stdc++.h>
using namespace std;

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

const int dim=1e5+9;

struct elem{
    int x,nr;
};

bool fv[dim];
vector<elem>v[dim];
vector<int>ans;
stack<int>stiva;

signed main(){
    int n,m;
        fin>>n>>m;
    for(int i=1;i<=m;i++){
        int x,y;
        fin>>x>>y;
        v[x].push_back({y,i});
        v[y].push_back({x,i});
    }
    stiva.push(1);
    while(!stiva.empty()){
        int x=stiva.top();
        int len=v[x].size();
        if(len){
            int nr=v[x][len-1].nr;
            int y=v[x][len-1].x;
            if(!fv[nr]){
                fv[nr]=true;
                stiva.push(y);
            }
            v[x].pop_back();
        }
        else{
            stiva.pop();
            ans.push_back(x);
        }
    }
    int l=ans.size();
    for(int i=0;i<l-1;i++){
        fout<<ans[i]<<' ';
    }
}