def length_of_last_word(s):  
        words = s.split()  
        if len(words) == 0:  
            return 0  
        return len(words[-1])  
  
print(length_of_last_word("Python Exercises"))  
print(length_of_last_word("Python"))  
print(length_of_last_word(""))  
print(length_of_last_word("  "))