Type
  tAlph = ^Alph;
  Alph = Record
           Ch : Char;
           Next : tAlph;
           Pred : tAlph;
         End;
Var
  A : tAlph;
 
Procedure ToBegin;
Begin
  While A^.Pred<>nil do A:=A^.Pred;
End;
 
Procedure InitAlphavit;
Var
  C : Char;
  B : tAlph;
Begin
  For C:='a' to 'z' do
  Begin
    New(B);
    B^.Ch:=C;
    B^.Pred:=A;
    If A<>nil then A^.Next:=B;
    B^.Next:=nil;
    A:=B;
  End;
End;
 
Procedure ShowSpis;
Var B : tAlph;
Begin
  ToBegin; B:=A;
  While B<>nil do
  Begin
    Write(B^.Ch,' ');
    B:=B^.Next;
  End;
  Writeln;
End;
 
Procedure DisposeAlphavit;
Var tmp : tAlph;
Begin
  ToBegin;
  While A<>nil do
  Begin
    tmp:=A;
    A:=A^.Next;
    Dispose(tmp);
  End;
End;
 
Begin
  A:=Nil;
  InitAlphavit;
  ShowSpis;
  DisposeAlphavit;
End.