N = int(input())
f = [[int(j) for j in input().split()] for i in range(N)]
dp = [-1 for i in range(1 << N)]
def dfs(S):
	if S == (1<<N)-1:
		return 0
	if dp[S] != -1:
		return dp[S]
	ret = 0
	for i in range(N):
		if S>>i&1:
			continue
		for j in range(i+1,N):
			if S>>j&1 or i == j:
				continue
			ret = max(ret,dfs(S | 1 << i | 1 << j) + f[i][j])
	dp[S] = ret
	return ret
print(dfs(0))