Least Downtime Server

Find the server with the lowest total downtime, breaking ties toward the most recently introduced server.

A hosting provider logs maintenance events across its server fleet. You are given a list of events, each naming the server and how many minutes it was down for, in the order the events happened. Add up the downtime minutes for each server. Return the server with the lowest total downtime. If two or more servers are tied for the lowest total, return whichever of them was introduced most recently in the log.