Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE user_profiles (followers INTEGER, UID VARCHAR); CREATE TABLE tweets (followers INTEGER, UID VARCHAR)
### Question:
Find the average number of followers for the users who do not have any tweet.
### Answer:
SELECT AVG(followers) FROM user_profiles WHERE NOT UID IN (SELECT UID FROM tweets)