import sequtils,strutils,algorithm

proc powInt(n : int64, m : int64, k = 1_000_000_007):int64 =
    if m == 0:
        return 1
    elif m == 1:
        return (n mod k)
    if (m mod 2) == 0:
        return powInt((n*n) mod k,m div 2, k) mod k
    else:
        return (powInt((n*n) mod k,m div 2, k) * n) mod k
proc IToS(i : int):string =
    return $ i
proc CToI(c : char): int =
    return int(c) - int('0')
proc BinSToInt(s : string):int =
    var s2 : string
    if s[0..1] == "0b":
        s2 = s[2..<s.len]
    else:
        s2 = s
    var ans = 0
    for index,item in s2:
        ans += (item.CToI * powInt(2,s2.len - 1 - index).int)
    return ans
let n = readline(stdin).parseInt
var
    ans = 0
    i,j,num,r,l : int
    s = newSeq[int](n)
    A = repeat(s,n)
    B = newSeqWith(n div 2,newSeq[int](0))
    Blist = newSeq[int](0)
for i in 0..<n:
    A[i] = readline(stdin).split.map(parseInt)
var S = newSeq[int](powInt(2,n + 1))
for i in countup(2,n,2):
    s = repeat(0, n - i) & repeat(1, i)
    var flag = true
    while flag :
        num = ("0b" & s.join()).BinSToInt
        r = -1
        l = -1
        for index,item in s:
            if item == 1 and l == -1:
                l = index
            elif item == 1:
                r = index
        if i == 2:
            S[num] = A[l][r]
            B[0].add(num)
        else:
            var Max_sum = 0
            for b in B[(i div 2) - 2]:
                if (b and num) == b:
                    j = (b xor num)
                    var i2 = S[j]
                    if Max_sum < i2 + S[b]:
                        Max_sum = i2 + S[b]
            S[num] = Max_sum
            if i == n and Max_sum > ans:
                ans = Max_sum
            elif i != n:
                B[(i div 2) - 1].add(num)
        flag = s.nextPermutation()
echo ans