def is_palindrome(input):
    """
    Return True if input is palindrome, False otherwise.
    
    Args:
       input(str): input to be checked if it is palindrome
    """
    if len(input)<=1:
        return True
    else:
        first=input[0]
        last=input[-1]
        sub=input[1:-1]
        return (first==last) and is_palindrome(sub)

# Test Cases

print ("Pass" if  (is_palindrome("")) else "Fail")
print ("Pass" if  (is_palindrome("a")) else "Fail")
print ("Pass" if  (is_palindrome("madam")) else "Fail")
print ("Pass" if  (is_palindrome("abba")) else "Fail")
print ("Pass" if not (is_palindrome("Udacity")) else "Fail")

