static int numb() {
        boolean invalidinput = false;
        int n = 0;
        do {
            boolean iscorrect = false;
            try {
                BufferedReader input = new BufferedReader(new FileReader("D:\\input.txt"));
                String text = input.readLine();
                do {
                    System.out.print("Enter the number of sequence members ");
                    n = Integer.parseInt(text);
                    System.out.println(n);
                    iscorrect = enter(n, 10, 1);
                } while (iscorrect);
            } catch (FileNotFoundException e) {
                System.out.println("A file with the same name was not found");
                invalidinput = true;
            } catch (IOException e) {
                System.out.println("This file cannot be opened");
                invalidinput = true;
            } catch (NumberFormatException e) {
                System.out.println("Error! File contains invalid data");
                invalidinput = true;
            }
        } while (invalidinput);
        return n;
    }