/** This is topological sort for an acyclic graph 
    An acyclic graph has no cycles
    m=out[i][0] is the number of edges from vertex i
    out[i][1], ..., out[i][m] are endpoints of edges from i 
    Endpoints, namely edges, can be given in any order **/
int out[100][100];
int i, k, n, stack[100];
int visited[100]; char name[100]; 
dfs(int v)
{ int j,w,m;
  visited[v]=1; ;
  m=out[v][0];
  for (j=1; j<=m; j++) {
    w=out[v][j];
    if (visited[w]==0) {
      dfs(w);
    }
  }
  stack[k]=v; k++;  // When we leave v, v is recorded into stack
}
main(){
  /*** graph initialization. You can edit this part for any acyclic graph ***/
  out[1][0]=2; out[1][1]=3; out[1][2]=2;  
  out[2][0]=1; out[2][1]=3; out[2][2]=4; 
  out[3][0]=1; out[3][1]=5; 
  out[4][0]=1; out[4][1]=6; 
  out[5][0]=2; out[5][1]=6; out[5][2]=4;
  out[6][0]=0;  
  n=6;
  for(i=1;i<=n;i++)visited[i]=0;
  k=1;  
  dfs(1);
  for(i=k-1;i>=1;i--)printf("%d ", stack[i]); 
  printf("\n");
}