Sliding-Window Rate Limiter

Build the limiter that stops credential stuffing. The first line is n (1 ≤ n ≤ 4000). Each of the next n lines is t user — a timestamp in whole seconds (non-decreasing) and a user id.

A request at time t is allowed if that user has had fewer than 3 allowed requests with timestamp greater than t − 10. Denied requests don't count toward the limit. Print ALLOW or DENY for each request.