Delivery Forces

시간 제한2초메모리 제한1024 MB

요약

3의 배수인 n명의 배달원을 세 명씩 짝지어 각 팀 중간값의 합이 최대가 되도록 나눈다.

난이도: 보통10점 중 6점
유형: 그리디, 정렬, 배열
정답자: 아직 제출이 없습니다

문제

Gry finally becomes the Executive Courier Officer in "Universe Express". He has $n$ subordinate couriers with some delivery strength $f\_i$ . The delivery strength of a team of three people is the median of their strength, i.e., the middle element after the sorting. Please help Gry to split the couriers into $k$ teams of three people in order to maximize the total delivery strength of "Universe Express". The total strength is the sum of the strength of these $k$ teams.

입력

One line containing the number of couriers in the company, $n$ ( $1 \leq n \leq 10^6$ ), where $n$ is a multiple of $3$ .
One line containing the strengths of the $n$ couriers $f\_1$ $\ldots$ $f\_n$ ( $1 \le f \le 10^6$ ).

출력

The sole line of the output should contain the maximal strength of "Universe Express".

예제2

예제 1
입력
```
3
1 2 3
```
예상 출력
```
2
```
예제 2
입력
```
6
5 6 2 3 1 4
```
예상 출력
```
8
```