Given an array of n integers named elements, we can perform several steps on the array. In each step, we choose an elementsi from the array and delete it to earn elements i points; However, deleting elements i also deletes any integers equal to elements i + 1 and elements i  1 from elements. For exampls, if elements = [1,2,3,4], deleting 2 results in elements becoming [4] and earns us 2 points.
Compute the maxPoints function that has one parameter; an array of n integers named elements. The function must return a long integer denoting the maximum number of points we can earn by performing steps.
Constraints

1<= n <= 10 (to the power 5)

1 <= elements i <= 10 (to the power 5)
Sample Input : [3,4,2]
Output : 6
Explanation:
Given elements = [3,4,2], we maximize our score by performing the following steps:
 Delete 4 to earn 4 points, which also deletes 4  1 = 3 and elements becomes [2].
 Delete 2 to earn 2 points and elements become []
There are no more elements to delete, so we can't perform any more steps. The function returns the total number of points which is 4 + 2 = 6.