The customer service of a small online store is constantly getting a lot of requests. Employees are processing the requests one-by-one on a first-come-first-served basis.
Given the number n and a sequence of n logs from a single day at the customer service, print out which requests remained unsolved and will be processed on the following day (in the order they will be considered). ISSUE issue_id denotes that a new request with identifier issue_id was received, while SOLVED means that the first issue in the queue was successfully solved.
You can assume that at the beginning of the day there were no pending requests.
Tip: Use str.split(" ") to split an input string on the space.
