#include <iostream>
#include <vector>
#include <fstream>

const int MAXN = 100000 + 1;

using namespace std;

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

bool viz[MAXN];
vector<pair<int,int> >graf[MAXN];
int n,m;

void dfs(int nod){
    for(int i = 0; i < graf[nod].size(); i++){
        int curent = graf[nod][i].first;
        int label = graf[nod][i].second;
        if(!viz[label]){
            viz[label] = true;
            dfs(curent);
            out<<nod<<" ";
        }
    }

}

int main()
{
    in>>n>>m;
    int muchii = 0;
    for(int i = 1; i <= m; i++){
        int x,y;
        in>>x>>y;
        graf[x].push_back({y,++muchii});
        graf[y].push_back({x,muchii});
    }
    dfs(1);
    return 0;
}