typedef struct dList{
        struct dList *flink;
        struct dList *blink;
        int val;
} *dListe;



dListe add(dListe entry, int val)
{
  dListe elem;
  elem=malloc(sizeof(struct dList));
  elem->val=val;
  if (entry==NULL){
    elem->flink=NULL;
    elem->blink=NULL;
  }
  else {
    elem->flink=entry;
    elem->blink=NULL;
    entry->blink=elem;
  }
  entry=elem;
  return entry;
}