#include <fstream>
#define NMAX 1000
#define MMAX (NMAX*(NMAX-1)/2)
using namespace std;
ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

bool a[NMAX][NMAX];
int n, m,nr, start,sol[NMAX],ok;
bool uz[NMAX];
void citire();
void euler(int x);
int main()
{
    citire();
    start=1;
    sol[++nr]=start;
    euler(start);
    return 0;
}
void citire()
{
    int i, x, y;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        a[x][y]=a[y][x]=1;
    }
}
void euler(int x)
{
  int i;
  uz[x]=1;
  for(i=1; i<=n; i++)
    while(uz[i]==0&&a[x][i]==1)
    {
        a[x][i]=a[x][i]-1;
        euler(i);
    }
    sol[++nr]=i;
}
void afisare()
{
    int i;
    for(i=1;i<=nr;i++)
        fout<<sol[i]<<" "<<'\n';
    fout.close();
}