import java.util.*;

public class Myk {

    public static void main(String[] args) {
        List<String> numbers = new LinkedList<String>();
        Scanner scanner = new Scanner(System.in);

        System.out.println("Provide a number or type \"exit\" to end.");
        String input = scanner.next();
        while (! input.equals("exit")) {
            System.out.println("Provide a number or type \"exit\" to end.");
            numbers.add(input);
            input = scanner.next();
        }
        double result = dodaj(numbers.toArray(new String[1]));
        System.out.println("Result: " + result);
    }

    public static double dodaj(String... args) {
        double suma = 0;
        try {
            for (int i = 0; i < args.length; i++)
                suma += Double.valueOf(args[i]);
        } catch (NumberFormatException e) {
            System.out.println("At least one of provided values is not a number!");
            System.exit(1);
        }
        return suma;
    }

}