code: private int getMaxNumber(final int numberOfDigits) {
          int result = 0;
  
          for (int i = 0; i < numberOfDigits; i++) {
              result += (NUMERIC_SYTEM - 1) * Math.pow(NUMERIC_SYTEM, i);
          }
  
          return result;
      }
docs: Returns the maximum number, which can be created with a specific number of digits.
  
  @param numberOfDigits
  The number of digits as an {@link Integer} value
  @return The maximum number, which can be created with the given number of digits, as an
  {@link Integer} value