//PrimeNumbers.Java
import java.util.Scanner;


public class PrimeNumbers {
   public static void main(String[] args){
         Scanner keyboard = new Scanner(System.in);
         long isPrime;
         System.out.print("Please enter a number to check if it is prime: ");
         isPrime = keyboard.nextLong();
         boolean isD = false;
         if(isPrime < 2){
            isD = true;
            System.out.println("All negative numbers and 0 and 1 are not prime, so " + isPrime + " is not a prime number");
         }
         for(long i = (isPrime/2) + 1; i > 1; i--){
            if(isPrime % i == 0){
               System.out.println(isPrime + " is not a prime number because it is divisible by " + i);
               isD = true;
            }
         }
         long counter = (isPrime/2) + 1;

         while(counter > 1){
               if(isPrime % counter == 0){
               System.out.println(isPrime + " is not a prime number because it is divisible by " + counter);
               isD = true;
            }
            counter--;
         }
         if(isD == false) {
            System.out.println(isPrime + " is a prime number!!!");
         }
   }
}