unit Unit1;

interface

uses
   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
   Dialogs, StdCtrls;

type
   TForm1 = class(TForm)
     Edit1: TEdit;
     Edit2: TEdit;
     Label1: TLabel;
     Label2: TLabel;
     Button1: TButton;
     Edit3: TEdit;
     procedure Button1Click(Sender: TObject);
   private
     { Private declarations }
   public
     { Public declarations }
   end;

var
   Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var sy,sz,sk,al:string; p,k,n:integer;
begin
sy:=edit1.Text;
al:=edit3.text;
n:=length(sy);
for k:=1 to n do
     begin
     sk:=copy(sy,k,1);
     p:=pos(sk,al);
     if p = 1 then
       begin
       sk:=al[length(al)];
       end
     else
       begin
       sk:=pred(al[P]);
       end;
     insert(sk,sz,k);

     end;
edit2.Text:=sz;
end;

end.