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

max_mask = 1 << n
dp = [-1] * max_mask
dp[0] = 0

# Precompute masks for each bit count
precomputed_masks = [[] for _ in range(n + 1)]
for mask in range(max_mask):
    bc = bin(mask).count('1')
    precomputed_masks[bc].append(mask)

for bc in range(0, n + 1, 2):
    for mask in precomputed_masks[bc]:
        if dp[mask] == -1:
            continue
        
        # Find the first unused idol using bitwise operations
        not_mask = (~mask) & ((1 << n) - 1)
        if not_mask == 0:
            continue
        
        lsb = not_mask & -not_mask
        first = (lsb).bit_length() - 1
        
        # Generate all possible pairs with the first unused idol
        not_mask_j = not_mask & (~((1 << (first + 1)) - 1))
        remaining = not_mask_j
        while remaining:
            lsb_j = remaining & -remaining
            j = (lsb_j).bit_length() - 1
            remaining ^= lsb_j
            
            new_mask = mask | (1 << first) | (1 << j)
            new_score = dp[mask] + F[first][j]
            if new_score > dp[new_mask]:
                dp[new_mask] = new_score

print(dp[(1 << n) - 1])