题号：NC50895
时间限制：C/C++/Rust/Pascal 4秒，其他语言8秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
时间限制：C/C++/Rust/Pascal 4秒，其他语言8秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
题目描述
Given 2N people, you need to assign each of them into either red team or white team such that each team consists of exactly N people and the total competitive value is maximized.
Total competitive value is the summation of competitive value of each pair of people in different team.
The equivalent equation is )
输入描述:
The first line of input contains an integers N.
Following 2N lines each contains 2N space-separated integersis the j-th value of the i-th line which indicates the competitive value of person i and person j.
*
*
*
输出描述:
Output one line containing an integer representing the maximum possible total competitive value.