import static java.lang.System.out;
import java.util.Optional;
 
class HelloWorld {
 
    public static void main(String[] args) {
        var name = at(args, 0).orElse("World");
        out.printf("Hello, %s!%n", name);
    }
 
    public static <T> Optional<T> at(T[] array, int index) {
        try {
            return Optional.of(array[index]);
        } catch (ArrayIndexOutOfBoundsException | NullPointerException e) {
            return Optional.empty();
        }
    }
 
}