#include <fstream>
#include <iostream>
#include <vector>
#include <bitset>
#include <string.h>
#include <algorithm>
#include <iomanip>
#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <stack>

using namespace std;

const char infile[] = "ciclueuler.in";
const char outfile[] = "ciclueuler.out";

ifstream fin(infile);
ofstream fout(outfile);

const int MAXN = 100005;
const int oo = 0x3f3f3f3f;

typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;

const inline int min(const int &a, const int &b) { if( a > b ) return b;   return a; }
const inline int max(const int &a, const int &b) { if( a < b ) return b;   return a; }
const inline void Get_min(int &a, const int b)    { if( a > b ) a = b; }
const inline void Get_max(int &a, const int b)    { if( a < b ) a = b; }

class UndirectedGraph {
public:
    UndirectedGraph(int N) {
        adj.resize(N);
    }
    void addUndirectedEdge(int x, int y) {
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    vector <int> getEulerianCycle(int Start) {
        st.push(Start);
        vector <int> euler;
        while(!st.empty()) {
            int node = st.top();
            if(!adj[node].size()) {
                st.pop();
                if(!st.empty())
                    euler.push_back(node);
            }
            else {
                int newnode = adj[node].back();
                adj[node].pop_back();
                st.push(newnode);
                adj[newnode].erase(find(adj[newnode].begin(), adj[newnode].end(), node));
            }
        }
        return euler;
    }
private:
    vector<vector <int> >adj;
    stack<int>st;
};

int N, M;

int main() {
    fin >> N >> M;
    UndirectedGraph G(N);
    for(int i = 1 ; i <= M ; ++ i) {
        int x, y;
        fin >> x >> y;
        G.addUndirectedEdge(x - 1, y - 1);
    }
    for(auto it: G.getEulerianCycle(0))
        fout << it + 1 << ' ';

    fin.close();
    fout.close();
    return 0;
}