#include <fstream>
using namespace std;

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

int v[101], n, a[101][101], p, q, t[101];

void citire()
{
    fin >> n >> p >> q;
    int i, j;
    while (fin >> i >>j)
        a[i][j] = a[j][i] = 1;
}

void BFS(int start)
{
    int st, dr, Q[101];
    st = 1;
    dr = 0;
    Q[++dr] = start;
    v[start] = 1;
    t[start] = 0;
    while(st<=dr)
    {
        int k = Q[st];
        for (int i=n; i>=1; i--)
            if(a[k][i]==1 && v[i]==0)
            {
                Q[++dr] = i;
                v[i] = 1;
                t[i] = k;
            }
        st++;
    }

}

void reconstituire(int stop)
{
     int S[101], top=0;
     while (stop!=0)
     {
         S[++top] = stop;
         stop = t[stop];
     }
     fout << top << '\n';
     while (top!=0)
        fout << S[top--] << " ";
}

int main()
{
    citire();
    BFS(p);
    reconstituire(q);
    return 0;
}