Now Serving

The NOW SERVING sign shows whoever stands at the front. 🔔

You get commands (join:name / serve, serves valid). After processing them all, print who the sign shows now — or no line if it's empty.

Example:

Input: commands = ["join:ana", "join:raj", "serve"] Output: raj

Ana joins, raj joins, then serve removes ana from the front — raj is now at the front, so the sign shows raj.