# coding: utf-8
import array, bisect, collections, copy, heapq, itertools, math, random, re, string, sys, time
sys.setrecursionlimit(10 ** 7)
INF = 10 ** 20
MOD = 10 ** 9 + 7


def II(): return int(input())
def ILI(): return list(map(int, input().split()))
def IAI(LINE): return [ILI() for __ in range(LINE)]
def IDI(): return {key: value for key, value in ILI()}


def read():
    n = II()
    F = IAI(n)
    return (n, F)


def solve(n, F):
    l_pair = [cmb for cmb in itertools.combinations(range(n), 2)]
    l_all = []
    for pairs in itertools.combinations(l_pair, n // 2):
        tmp_set = set()
        for pair in pairs:
            tmp_set.add(pair[0])
            tmp_set.add(pair[1])
        if len(tmp_set) == n:
            l_all.append(pairs)

    ans = 0
    for pair_cmb in l_all:
        tmp = 0
        for pair in pair_cmb:
            tmp += F[pair[0]][pair[1]]
        ans = max(ans, tmp)

    return ans


def main():
    params = read()
    print(solve(*params))


if __name__ == "__main__":
    main()