procedure TForm1.Button1Click(Sender: TObject);
var
  A, B: string;
begin
  A := '123ABC 123ABC 123ABC 123ABC 123ABC';
  B := '123';
  Label1.Caption := IntTostr(CountOf(A, B));
end;    function TForm1.CountOf(A, B: string): Integer;
var
  P: Integer;
begin
  Result := 0;
  P := Pos(B, A);
  while P > 0 do
  begin
    Inc(Result);
    A := Copy(A,P Length(B),Length(A)-P-Length(B) 1);
    P := Pos(B, A);
  end;
end;