The Hybrid Checkout Ratio

A supermarket has one cashier serving two queues: 'Express' (customers with 5 or fewer items) and 'Regular'. To keep the express line moving, the cashier follows a strict 2-to-1 ratio: they serve 2 customers from Express, then 1 from Regular. If a queue is empty, the cashier serves whoever is available from the other queue. If both have customers, the ratio rule must be reset only after a Regular customer is served or if the Express queue becomes empty. Input: N (number of customers). Then N lines: 'E' or 'R' (Queue Type) followed by the customer name. Output: The names in the order they are served. Example: Input: 4 E Alice E Bob E Charlie R Dave Output: Alice Bob Dave Charlie