import java.util.Scanner;

public class Demo1{

    public static void main(String []args){

        // Java standard output
        System.out.println("Hello World");

        // Java standard input
        Scanner scanner = new Scanner(System.in);
        int age = scanner.nextInt();
        System.out.println("I am " + age + " years old.");

        // math subtilty
        System.out.println("5 / 2 = " + 5/2); // result is integer
        System.out.println("5 / 2.0 = " + (-5)/2.0); // result is precise
        System.out.println("(-5) % 2 = " + (-5)%2); // result is negative

    }
}