Freight Elevator

Boxes stack up in the freight elevator; the safety inspector wants its heaviest moment of the day. 🛗

You get commands — load:250 (a box of that weight goes on top) or unload (top box off, always valid). Print the maximum TOTAL weight the elevator held at any moment.

Example:

Input: commands = ["load:100", "load:200", "unload", "load:50"] Output: 300

The total weight climbs to 100, then 300 (the peak), drops to 100 after unloading, then rises to 150 — the highest total ever reached was 300.