rambless

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        Map<String, String> map = new HashMap<>();
        map.put("reset", "reset what");
        map.put("reset board", "board fault");
        map.put("board add", "where to add");
        map.put("board delete", "no board at all");
        map.put("reboot backplane", "impossible");
        map.put("backplane abort", "install first");

        Map<Key, String> keys = new HashMap<>();
        keys.put(new Key("reset", "board"), "");
        keys.put(new Key("board", "add"), "");
        keys.put(new Key("board", "delete"), "");
        keys.put(new Key("reboot", "backplane"), "");
        keys.put(new Key("backplane", "abort"), "");
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String str = in.nextLine();
            match(str, keys, map);
        }
    }

    private static void match(String str, Map<Key, String> keys, Map<String,String> map) {
        String[] arr = str.split(" ");
        if(arr.length>2) {
            System.out.println("unknown command");
        }
        if(arr.length==1) {
            if("reset".startsWith(arr[0])) {
                System.out.println("reset what");
            } else {
                System.out.println("unknown command");
            }
            return;
        }
        int count = 0;
        String s = "";
        for(Key key : keys.keySet()) {
            //依次比较，成功后count++
            if(key.a.startsWith(arr[0])) {
                if(key.b.startsWith(arr[1])) {
                    count++;
                    s = key.a + " " + key.b;
                }
            }
        }
        if(count==1) {
            System.out.println(map.get(s));
        } else {
            System.out.println("unknown command");
        }
    }

    static class Key {
        String a;
        String b;
        public Key(String a, String b) {
            this.a = a;
            this.b = b;
        }
    }
}