import java.util.Scanner;

public class Work {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Double sum = 0.0;
        while (true){

            System.out.println("输入学生成绩");
            Double score = sc.nextDouble();
            if(score == -1 ){
                break;
            }else {
//                sum += score;
                sum = sum + score;

            }

        }
        System.out.println("总成绩为："+sum);
    }
}