public static boolean isPalindrome2(int x) {//pass
        //negative numbers are not palindrome
        if (x < 0) {
            return false;
        }

        long x_bak = x;
        long x_new = 0;
        while (x != 0) {
            x_new = x_new * 10;
            x_new += x % 10;
            x = x / 10;
        }

        System.out.println(x_new);
        if (x_bak == x_new) return true;
        else return false;
    }