def is_palindrome(s):
    if len(s) <= 1 or s[0] == s[-1]:
        return is_palindrome(s[1:-1])
    return False


if __name__ == '__main__':
    result = is_palindrome("abccba")
    print(result)

    result = is_palindrome("abccbaf")
    print(result)

    result = is_palindrome("a")
    print(result)