Write a method that returns how much defensive power Smaug had after he is attacked. Parameters are as follows: 'power'>=0 is how powerful the attack is; 'defense'>=0 is Smaug's basic defense level; 'scales', if true indicates that Smaug's defense level should be doubled; 'gems', if true indicates that Smaug's defense level should be tripled. However, if BOTH gems and scales are true Smaug's basic defenses are multiplied by 7. Return the difference between Smaug's total defense and the power he is being hit with. For example: smaugHitPoints(4, 10, false, false) returns 6 since 10-6=4. smaugHitPoints(3, 20, true, false) returns 37 since 40 (double 20) - 3 = 37