#include<fstream.h>

ifstream f("date.in");
ofstream g("date.out");

struct nodd{int info;
	    nodd *prec,*urm;
	   };
    nodd *prim;

void adaugs(nodd *&prim,int x)
 {nodd *u=prim;
  if(prim)
   {while(u->urm)   u=u->urm;
    nodd *nou=new nodd;
    nou->info=x;
    u->urm=nou;
    nou->prec=u;
    nou->urm=0;
   }
    else {prim=new nodd;
	  prim->info=x;
	  prim->urm=0;
	  prim->prec=0;
	 }
 }

void creare(nodd *&prim)
 {int x;
  while(f>>x) adaugs(prim,x);
 }

 void afis(nodd *prim)
  {nodd *p=prim;
  while(p->urm) {g<<p->info<<" ";
		 p=p->urm;
		}
  g<<p->info<<" ";
  g<<endl;
  while(p) {g<<p->info<<" ";
	    p=p->prec;
	   }
           g<<endl;
 }

void inseraredupa(nodd *p,int x)
 {nodd *nou=new nodd;
  nou->info=x;
  nodd*q=p->urm;
  nou->prec=p;
  p->urm=nou;
  nou->urm=q;
  if(q) q->prec=nou;
 }

void sterg(nodd *&p)
 {nodd *q,*r;
  q=p->prec;
  r=p->urm;
  if(r) r->prec=q;
  if(q) q->urm=r;
   else {nodd *x=p;
	 p=p->urm;
	 p->prec=0;
	 delete x;
	}
 if(p!=r) delete p;
}

void main()
 {creare(prim);
  afis(prim);
  inseraredupa(prim->urm,7);
  afis(prim);
  sterg(prim->urm->urm);
  afis(prim);
  sterg(prim);
  afis(prim);
 }