Given the following recursive method: public static int f(int num) { if(num < 2) return 1; else if(num % 2 == 0) return f(num / 2); else return f(3 * num + 1); }

How many recursive calls are made by the following initial calls? System.out.println(f(7)); System.out.println(f(8)); System.out.println(f(15)); System.out.println(f(16));