import itertools

input = raw_input
range = xrange

def read_data():
    n = int(input())
    F = [list(map(int, input().split())) for _ in range(n)]
    return n, F

def solve(n, F):
    dp = [0] * (1 << n)
    mmax = max
    for mask in range(1, 1 << n):
        if (bin(mask).count('1') & 1): continue
        pos = [i for i in range(n) if mask & (1 << i)]
#        if (len(pos) & 1): continue
        val = 0
        for i, j in itertools.combinations(pos, 2):
            tmp = dp[mask - (1 << i) - (1 << j)] + F[i][j]
            if tmp > val: val = tmp
        dp[mask] = val
    return dp[-1]

n, F = read_data()
print(solve(n, F))