Delivery Forces
Description
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.
- 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 $f_1$...$f_n$ ($1 \le f \le 10^6$).
The sole line of the output should contain the maximal strength of "Universe Express".
Input
- 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 $f_1$...$f_n$ ($1 \le f \le 10^6$).
Output
The sole line of the output should contain the maximal strength of "Universe Express".
3
1 2 3
6
5 6 2 3 1 4
2
8