Problem with deleting a node in doubly-linked list. Help me plz)

1
2
2
2
5
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7
7
7
0
1
2
3
4
5
6
7
18
19

program silly;

type
        ListType=^ElementType;
        ElementType = record
            next:ListType;
            data:integer;
            prev:ListType;
            end;
var something,Cursor,TheFirst:ListType;
    f:text;
    i:integer;
procedure DeleteThoseSillyIdenticalElements();
    begin
        Cursor:=TheFirst;
        while Cursor^.next<>nil do
            begin
                writeln(Cursor^.data);
                    if Cursor^.data=Cursor^.next^.data then
                        begin
                            if Cursor^.next<>nil then
                                Cursor^.next^.prev:=Cursor^.prev;
                            if Cursor^.prev<>nil then
                                Cursor^.prev^.next:=Cursor^.next;
                            dispose(Cursor);

                        end;
                Cursor:=Cursor^.next;

            end;
    end;
begin
assign(f,'a.txt');
reset(f);
  new(something);
  something^.data:=4;
  something^.prev:=nil;
  something^.next:=nil;
  
  for i:=1 to 19 do
    begin
        New(Cursor);
        Readln(f,Cursor^.data);
        Cursor^.prev:=something;
        Cursor^.next:=nil;
        something^.next:=Cursor;
        if i=1 then TheFirst:=Cursor;
        something:=Cursor;
    end;
DeleteThoseSillyIdenticalElements();
  close(f);
  readln();
end.