# include <iostream>
# include <fstream>
# include <vector>
# include <bitset>
using namespace std;

# define MAXN 50010
# define MAXM 100010

ifstream f("sortaret.in");
ofstream g("sortaret.out");

int n, m;
vector<pair<int, int> > G[MAXN];
bitset<MAXM> vizmuchie;

int dfs(int nd = 1)
{
    g << nd << ' ';
    for (int i = 0; i < G[nd].size(); i++) {
        if (vizmuchie[G[nd][i].second] == false) {
            vizmuchie[G[nd][i].second] = true;
            dfs(G[nd][i].first);
        }
    }
}

int main()
{
    f >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y;
        f >> x >> y;
        G[x].push_back(make_pair(y, i));
        G[y].push_back(make_pair(x, i));
    }

    dfs();

    return 0;
}