未定义的标签LOOP1

import
import
import

public class T3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        while(true){
            System.out.println("请输入一个成绩：");
            try
             { BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
               int mark = Integer.parseInt(in.readLine());//强制转换为int的类型
               if(mark>=0 && mark<=100)
               {mark = mark/10;
                switch(mark)
                   {case 0:
                    case 1:
                    case 2:
                    case 3:
                    case 4:
                    case 5:System.out.println("E级");break;
                    case 6:System.out.println("D级");break;
                    case 7:System.out.println("C级");break;
                    case 8:System.out.println("B级");break;
                    case 9:
                    case 10:System.out.println("A级");break;
                   }
                }   
               else
               continue ;
               }catch(IOException e){
                   
               }
        }
    }

}

怎么没有人理我啊？？