using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace _06_PrimeChecker { class Program { static void Main(string[] args) { long n = long.Parse(Console.ReadLine()); Console.WriteLine(IsPrime(n)); } private static bool IsPrime(long n) { if (n == 2) { return true; } if (n % 2 == 0 || n == 1) { return false; } for (int i = 3; i <= (long)Math.Sqrt(n); i+=2) { if (n % i == 0) { return false; } } return true; } } }