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 xrange(1, 1 << n):
        pos = [i for i in range(n) if mask & (1 << i)]
        if len(pos) & 1: continue
        val = 0
        for i in pos:
            Fi = F[i]
            for j in pos:
                if j >= i:
                    break
                val = mmax(val, dp[mask - (1 << i) - (1 << j)] + Fi[j])
        dp[mask] = val
    return dp[-1]

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