#include <fstream>
#define lim 10001
using namespace std;
ifstream f ("date.in");
ofstream g ("date.out");
int n, m;
int mat[lim][lim];
int coada[lim];
int start;
int p, u;
bool verif[lim];
void read ()
{
    f>>n>>m;
    for (int i=1;i<=m;++i)
    {
        pair<int, int>element;
        f>>element.first>>element.second;
        mat[element.first][element.second] = 1;
        mat[element.second][element.first] = 1;
    }
    f>>start;
}
void init ()
{
    coada[1] = start;
    verif[start] = true;
    p = 1;
    u = 1;
}
void bfs ()
{
    while (p <= u)
    {
        int v = coada[p];
        ++p;
        for (int i=1;i<=m;++i)
            if (mat[v][i] == 1 && verif[i] == false)
            {
                ++u;
                coada[u] = i;
                verif[i] = true;
            }
    }
}
int main()
{
    read();
    init();
    bfs();
    g<<start<<'\n';
    for (int i=1;i<=n;++i)
        g<<coada[i]<<' ';
    return 0;
}