Boredom

Source: Codeforces

Version: Phuoc Hung OJ Extended

Problem Statement

Given an array $a$, in one move choose a remaining value $x$, gain $x$ points, and delete all remaining elements equal to $x-1$ and $x+1$. Continue as desired and maximize total score.

Input

Line 1 contains $n$. Line 2 contains $a_1,\ldots,a_n$.

Output

Print the maximum score.

Subtasks

• Subtask 1 — 20 points: n <= 20; a_i <= 30.
• Subtask 2 — 30 points: n <= 5000; a_i <= 5000.
• Subtask 3 — 50 points: 1 <= n <= 100000; 1 <= a_i <= 100000.

Examples

Input

3
1 2 3

Output

4

Explanation

Choosing values 1 and 3 yields $1+3=4$, better than choosing 2 for 2 points.