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

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
        f(null);
        f((String[]) null);

        System.out.println("---");

        String s = null;
        f(s == null ? null : new String[] { s });
        s = "hello, world";
        f(s == null ? null : new String[] { s });

        System.out.println("---");

        f();
        f("hello");
        f("hello", "world");

        System.out.println("---");

        f(new String[0]);
        f(new String[] { "hello" });
        f(new String[] { "hello", "world" });
    }

    public static void f(String... s) {
        System.out.println(s == null ? "null" : s.length);
    }
}