import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args)  {
        BufferedReader s = new BufferedReader( new InputStreamReader(System.in)) ;
        System.out.println("Hello World!");
        try {
            String str = s.readLine();
        }catch (Exception e ){}
    }
}

Scanner in = new Scanner(System.in);

int i = in.nextInt();
String s = in.next();



public static void main(String[] args) {

    // ====
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    System.out.print("Please enter user name : ");
    String username = null;
    try {
        username = reader.readLine();
    } catch (IOException e) {
        e.printStackTrace();
    }
    System.out.println("You entered : " + username);

    // ===== In Java 5, Java.util,Scanner is used for this purpose.
    Scanner in = new Scanner(System.in);
    System.out.print("Please enter user name : ");
    username = in.nextLine();      
    System.out.println("You entered : " + username);


    // ====== Java 6
    Console console = System.console();
    username = console.readLine("Please enter user name : ");   
    System.out.println("You entered : " + username);

}