void SortedInsert(struct Node *p, int x){
  
  struct Node *t, *q= NULL;
  t= (struct Node *)malloc(sizeof(struct Node));
  t->data= x;
  t->next= NULL;
  
  if (first == NULL)
    first = t;
  else{
    while(p && p->data <x){
      q=p;
      p=p->next;
      }
    if (p==first){
      t->next=first;
      first=t;
    } else {
      t->next = q->next;
      q->next= t;
    }
  }
}