#include <fstream>
#define N 105

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

int p,q; //cele 2 noduri date
int a[N][N],n,m; //listele de adiacenta
int Q[N],prim,ultim; //coada pentru BFS
int viz[N];
int L[N];
int T[N];

void Citire()
{ int x,y;
  fin>>n>>p>>q;
  while(fin>>x)
    { fin>>y;
      a[x][0]++;
      a[x][a[x][0]]=y;
      a[y][0]++;
      a[y][a[y][0]]=x;
    }
}

void BFS(int x)
{ int i,v,y;
  Q[1]=x; prim=ultim=1;
  viz[x]=1; L[x]=0; T[x]=0;
  while(prim<=ultim)
     { v=Q[prim]; prim++;
       for(i=1;i<=a[v][0];i++)
          { y=a[v][i];
            if(viz[y]==0)
              { viz[y]=1;
                ultim++; Q[ultim]=y;
                L[y]=L[v]+1;
                T[y]=v;
              }
          }
     }
}

void Lant(int x)
{ if(T[x]!=0) Lant(T[x]);
  fout<<x<<" ";
}

void Afisare()
{ fout<<L[q]<<"\n";
  Lant(q);
}

int main()
{ Citire();
  BFS(p);
  Afisare();
    return 0;
}