n = int(input())
f = [list(map(int, input().split())) for i in range(n)]
dp = [-1] * (1 << n)


def solve(state):
    if dp[state] != -1:
        return dp[state]
    if state == (1 << n) - 1:
        return 0
    ret = 0
    for i in range(n):
        if state & (1 << i):
            continue
        for j in range(i, n):
            if state & (1 << j):
                continue
            ret = max(ret, solve(state | (1 << i) | (1 << j)) + f[i][j])
    dp[state] = ret
    return ret


print(solve(0))