You are going to act as a Python interpreter. You will be given a valid python program below. Write down what you think the result of its execution would be. Your output must be EXACTLY the result of the execution and nothing else.
situation
system
class CountUniqueWords:

    def __init__(self, sentence):
        self.sentence = sentence
        self.unique_words = []
    
    def count_unique_words(self):
        words = self.sentence.split()
        for word in words:
            if word not in self.unique_words:
                self.unique_words.append(word)
        return len(self.unique_words)

sentence = "Hello world. This is a sample sentence."
c = CountUniqueWords(sentence)
print(c.count_unique_words())
user
7
assistant