Is It a Mountain?

A proper mountain climbs, hits one peak, then descends — no flat parts, no double peaks. ⛰️

You get at least 3 nums. Print mountain if they strictly rise then strictly fall (with the peak somewhere in the middle), otherwise not a mountain.

Example:

Input: nums = [1, 4, 7, 5, 2] Output: mountain

It strictly climbs 1 → 4 → 7, peaks at 7, then strictly falls 7 → 5 → 2 — a real mountain.