// Author: Rodney Shaghoulian // Github: github.com/RodneyShag // HackerRank: hackerrank.com/RodneyShag import java.util.Scanner; import java.math.BigInteger; /* I use isProbablePrime() with certainty = 10 to achieve 99.9% accuracy. However, even certainty = 1 (which achieves 50% accuracy) is enough to pass the HackerRank test cases. isProbablePrime() is always 100% certain if it tells you if a number is "not prime". If it says "prime", it's only 99.9% certain. It may be the case that it just hasn't found a prime number number that divides the BigInteger yet. */ public class Solution { public static void main(String[] args) { Scanner scan = new Scanner(System.in); BigInteger n = scan.nextBigInteger(); scan.close(); System.out.println(n.isProbablePrime(10) ? "prime" : "not prime"); } }