public boolean isPalindrome(String inputString) {
        inputString = inputString.toLowerCase(); //since its case insensitive
        //An empty string is a palindrome
        if (inputString == null || inputString.length() == 0)
            return true;

        int low = 0;
        int high = inputString.length()-1;

        while (low < high)  {
            if (inputString.charAt(low) < 'a' || inputString.charAt(high) > 'z') {
                low = low + 1;
                continue;
            }
            if (inputString.charAt(high) < 'a' || inputString.charAt(high) > 'z') {
                high = high - 1;
                continue;
            }
            if (inputString.charAt(low) != inputString.charAt(high))
                return false;
            low = low + 1;
            high = high - 1;
        }

        return true;
    }