p03767 AtCoder Grand Contest 012 - AtCoder Group Contest
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
```python
N = int(input())
A = list(map(int, input().split()))

A.sort()
print(sum(A[N:3 * N:2]))
```