private void verify() {
        if(!input.isEnabled()) {
            return;
        }
        
        String text = ((JTextField) input).getText();

        if(text.length() == 0) {
            return;
        }

        boolean valid = false;
        try {
            BigInteger value = new BigInteger(input.getText());
            valid = value.compareTo(bMin) >= 0 && value.compareTo(bMax) <= 0;
        } catch(NumberFormatException e) {
            // Not a number at all, replace with last input
            valid = false;
        }

        if(!valid)
            input.setForeground(Color.RED);
        else {
            input.setForeground(Color.BLACK);
        }
    }