public ArrayList<ArrayList<String>> readData() throws IOException {
        ArrayList<ArrayList<String>> datas = new ArrayList<ArrayList<String>>();
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String str = "";
        while (!(str = reader.readLine()).equals("")) {
            StringTokenizer tokenizer = new StringTokenizer(str);
            ArrayList<String> s = new ArrayList<String>();
            while (tokenizer.hasMoreTokens()) {
                s.add(tokenizer.nextToken());
            }
            datas.add(s);
        }
        return datas;
    }