Здравствуйте, Vajik!

Код Lazarus[code lang=pascal h=300]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

{ TForm1 }

TForm1 = class(TForm)
Edit1: TEdit;
Label1: TLabel;
procedure Edit1KeyPress(Sender: TObject; var Key: char);
procedure FormCreate(Sender: TObject);
private
function Check(a:string):string;
public

end;

var
Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }
function TForm1.Check(a:string):string;
var
b,c,d,e:integer;
begin
c:=0;d:=0;e:=0;a:=a+#2;
for b:=1 to length(a)-1 do
if a[b]=a[b+1]then
if a[b]<>a[b+2] then
begin
inc(e);
if c=0 then c:=b else d:=b;
end
else a[b+2]:=#1;
case e of
0:Check:='not found couple';
1:Check:='only one couple, positions:='+IntToStr(c)+','+IntToStr(c+1)+' '+a[c]+a[c+1];
else Check:=IntToStr(e)+' couples, first:='+IntToStr(c)+','+IntToStr(c+1)+' '+a[c]+a[c+1]+
' last:='+IntToStr(d)+','+IntToStr(d+1)+' '+a[d]+a[d+1];
end;

end;

procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: char);
begin
if Key=#13 then
begin
Edit1.ReadOnly:=True;
Label1.Caption:=Check(Edit1.Text);
Label1.Show;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
label1.Hide;
end;

end. [/code]

Удачи!