// IN_STACK[v]=1 means v is in STACK. out[v][0] is size of OUT(v)
// Vertices are give by integers. Name[] holds their names
int out[100][100];
int c, N[100], L[100], STACK[100], IN_STACK[100];
int visited[100]; char name[100]; int i,n,p;
push(v){
  IN_STACK[v]=1; p++; STACK[p]=v; 
}
pop(v){  // Pops up from top to v
  int w=STACK[p];
  while (STACK[p]!=v){
    printf("%c ",name[w]); IN_STACK[w]=0;
    p--; w=STACK[p];
  }
  printf("%c ",name[w]);
  IN_STACK[w]=0; p--; printf("\n");
}
int min(int x, int y){
  if (x<=y) return x; else return y;
}
dfs(int v)
{ int j,w,m;
  visited[v]=1; N[v]=c; c++;
  push(v); L[v]=N[v];
  m=out[v][0];
  for (j=1; j<=m; j++) {
    w=out[v][j];
    if (visited[w]==0) {
      dfs(w);
      L[v]=min(L[v], L[w]);
    }
    else
    if ((N[w]<L[v])&&(IN_STACK[w]==1)) 
      L[v]=min(N[w], L[v]);
  }
    if (L[v]==N[v]) pop(v);
}
main(){
  out[1][0]=3; out[1][1]=5; out[1][2]=7; out[1][3]=2; 
  out[2][0]=1; out[2][1]=7; 
  out[3][0]=4; out[3][1]=2; out[3][2]=9; out[3][3]=10; out[3][4]=4;
  out[4][0]=1; out[4][1]=10; 
  out[5][0]=1; out[5][1]=6; 
  out[6][0]=2; out[6][1]=5; out[6][2]=1; 
  out[7][0]=1; out[7][1]=6; 
  out[8][0]=2; out[8][1]=3; out[8][2]=7; 
  out[9][0]=2; out[9][1]=8; out[9][2]=10; 
  out[10][0]=0; 
  name[1]='a'; name[2]='b'; name[3]='c'; name[4]='d'; name[5]='e';
  name[6]='f'; name[7]='g'; name[8]='h'; name[9]='i'; name[10]='j';
  c=1; p=0;
  for (i=1; i<=n; i++) {visited[i]=0; IN_STACK[i]=0;}
  dfs(3);
}