题目描述
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.
Examples
Input
2
5 2 8 5 1 5
Output
10
Input
10
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000
Output
10000000000
输入格式
见题面
输出格式
见题面