public static String readString() throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        final String s = br.readLine();
        br.close();
        return s;
    }
    
    public static int readInt() throws IOException, NumberFormatException {
        return Integer.parseInt(readString());
    }
    
    public static int readDouble() throws IOException, NumberFormatException {
        return Double.parseDouble(readString());
    }