B"Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game and decided to play it. Given a sequence a consisting of n integers. The player can make several steps. In a single step he can choose an element of the sequence (let's denote it ak) and delete it, at that all elements equal to ak xe2 x80 x89+ xe2 x80 x891 and ak xe2 x80 x89- xe2 x80 x891 also must be deleted from the sequence. That step brings ak points to the player. Alex is a perfectionist, so he decided to get as many points as possible. Help him. The first line contains integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89105) that shows how many numbers are in Alex's sequence. The second line contains n integers a1, a2, ..., an (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89105). Print a single integer -- the maximum number of points that Alex can earn. Consider the third test example. At first step we need to choose any element equal to 2. After that step our sequence looks like this [2, xe2 x80 x892, xe2 x80 x892, xe2 x80 x892]. Then we do 4 steps, on each step we choose any element equals to 2. In total we earn 10 points."...