Java Fast IO

import java.util.*;
import java.io.*;

public class Main {
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer st;
    static PrintWriter pw = new PrintWriter(System.out);

    public static void main(String[] args) throws IOException {
        int n = readInt();
        String s = next();  // reads a string (not necessarily an entire line!)
        String entireLine = readLine();
        double myDouble = readDouble();

        pw.println("Use PrintWriter -- it's faster!");
        pw.print("PrintWriter is shorter to write (compared to System.out.println)\n");
        pw.println("But be careful when using PrintWriter in interactive problems " +
            "use pw.flush() to make sure pw prints before the next input!");
        pw.flush();

        pw.close();  // always write this line before ending the program!!
    }

    static String readLine() throws IOException {
        return br.readLine().trim();
    }
    static String next() throws IOException {
        while(st == null || !st.hasMoreTokens())
            st = new StringTokenizer(readLine());
        return st.nextToken();
    }
    static int readInt() throws IOException {
        return Integer.parseInt(next());
    }
    static double readDouble() throws IOException {
        return Double.parseDouble(next());
    }
}