#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <string.h>
#define dMAX 100000

using namespace std;

int n, m, x, y, poz;
bool viz;
vector<pair<int, bool> > graf[dMAX + 2];
vector<int> muchii;
int d[dMAX + 2];

char sir[30];
int idx;

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

void GetInt(int &t) {
    t = 0;
    while (isdigit(sir[idx])) {
        t *= 10;
        t += (int)sir[idx] - '0';
        idx++;
    }
    idx++;
}

bool Compare(pair<int, bool> e1, pair<int, bool> e2) {
    return e1.first < e2.first;
}

void BinarySearch(int l, int r, int val, int idx, int &p) {
    if (l > r) return;
    else {
        int middle = (l + r) / 2;
        if (graf[idx][middle].first == val) {
            if (graf[idx][middle].second == false) {
                p = middle;
                BinarySearch(l, middle - 1, val, idx, p);
            } else {
                BinarySearch(middle + 1, r, val, idx, p);
            }
        } else {
            if (graf[idx][middle].first > val) {
                BinarySearch(l, middle - 1, val, idx, p);
            } else BinarySearch(middle + 1, r, val, idx, p);
        }
    }
}

void Euler(int v) {
    int newV, u, l, nn, siz;
    siz = graf[v].size();
    for (u = 0; u < siz; u++) {
        newV = graf[v][u].first;
        viz = graf[v][u].second;
        if (!viz) {
            graf[v][u].second = true;
            poz = 0;
            BinarySearch(0, siz, v, newV, poz);
            graf[newV][poz].second = true;
            Euler(newV);
        }
    }
    if (v != 1)
        fout << v << ' ';
}

int main()
{
    int i, j;
    fin >> n >> m;
    fin.get();
    for (i = 1; i <= m; i++) {
        idx = 0;
        fin.getline(sir, 30);
        GetInt(x);
        GetInt(y);
        graf[x].push_back({y, 0});
        graf[y].push_back({x, 0});
        d[x]++, d[y]++;
    }
    for (i = 1; i <= n; i++) {
        sort(graf[i].begin(), graf[i].end(), Compare);
    }
    fout << "1 ";
    Euler(1);

    return 0;
}