SumPrimeNotPrimeNumbers

public class SumPrimeNonPrime {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String input = scanner.nextLine();
        int sumPrime =0;
        int sumNotPrime=0;


        while (! input.equalsIgnoreCase("Stop")){
            int number = Integer.parseInt(input);
            int counter=0;
            if (number < 0){
                System.out.println("Number is negative.");
            }else {
                for (int i = 1; i <= number ; i++) {
                    if (number % i == 0){
                        counter++;

                    }

                }
                if (counter ==2){
                    sumPrime+=number;
                }else {
                    sumNotPrime+=number;
                }

            }


            input=scanner.nextLine();
        }

        System.out.printf("Sum of all prime numbers is: %d%n",sumPrime);
        System.out.println("Sum of all non prime numbers is: " + sumNotPrime);
    }
}