#include <fstream>
#include <vector>

using namespace std;

ifstream f("sortaret.in");
ofstream g("sortaret.out");
int viz[50001],n,m,a,b;
vector <int> v[50001];
void dfs(int x)
{
    viz[x]=1;
    g<<x<<" ";
    for(int i=0;i<v[x].size();i++)
        if(viz[v[x][i]]==0)
            dfs(v[x][i]);
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=n;i++)
    {
        f>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1);
    return 0;
}