from collections import * 

N = int(input())
F = []
for i in range(N):
    F.append(list(map(int, input().split())))
    
pre = defaultdict(int)
pre[0] = 0
for _ in range(N//2):
    dp = defaultdict(int)
    for k, v in pre.items():
        ind = -1
        for i in range(N):
            if (k >> i) & 1 == 0:
                ind = i
                break
        else:
            break
        for i in range(ind + 1, N):
            if (k >> i) & 1 == 0:
                nk = k | (1 << ind) | (1 << i)
                dp[nk] = max(dp[nk], v + F[ind][i])
    dp, pre = pre, dp
    
print(pre[(1 << N) - 1])