N = int(input())
A = tuple(tuple(map(int, input().split())) for _ in range(N))

dp = [0] * (1 << N)
for b in range(1 << N):
    if b.bit_count() % 2 == 1:
        continue
    for i in range(N):
        if b >> i & 1:
            continue
        for j in range(i + 1, N):
            if b >> j & 1:
                continue
            dp[b | 1 << i | 1 << j] = max(dp[b | 1 << i | 1 << j], dp[b] + A[i][j])
        break
print(dp[-1])