помогите)

public static void main(String[] args) throws Exception {
       BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        int sum = 0;

        while (true) {
            int n = Integer.parseInt(reader.readLine());
            sum = sum + n;
            if (n == -1) {
                System.out.println(sum);
                break;
            }
        }

}