Problem Statement

There are $3N$ participants in AtCoder Group Contest. The strength of the $i$-th participant is represented by an integer $a_i$. They will form $N$ teams, each consisting of three participants. No participant may belong to multiple teams.

The strength of a team is defined as the second largest strength among its members. For example, a team of participants of strength $1$, $5$, $2$ has a strength $2$, and a team of three participants of strength $3$, $2$, $3$ has a strength $3$.

Find the maximum possible sum of the strengths of $N$ teams.

Constraints

• $1 ≤ N ≤ 10^5$
• $1 ≤ a_i ≤ 10^{9}$
• $a_i$ are integers.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_{3N}

Output

Print the answer.