The Prime Detector

A prime refuses to be divided by anything but 1 and itself — the loners of the number world. 🔬

You get n (at least 2). Print prime or not prime. Bonus cleverness: why is it enough to test divisors only while divisor × divisor ≤ n?

Example:

Input: n = 13 Output: prime

No number from 2 up to √13 ≈ 3.6 divides 13 evenly, so it survives every test — prime.