import sequtils,strutils,math

proc p2(i : int):int =
    return 1 shl i

var
    N = stdin.readline.parseInt
    A = newSeqWith(N,newSeq[int](0))
    x : int
    B : array[0..p2(24),int]
    T : seq[int]
for n in 0..<N:
    A[n] = stdin.readline.split.map(parseInt)

for k in 1..<N:
    for j in 0..<k:
        x = p2(k) + p2(j)
        B[x] = A[k][j]

for i in 1..<p2(N):
    if B[i] == 0:
        continue
    for j in 0..<N:
        if (p2(j) and i) == 0:
            for k in j+1..<N:
                if (p2(k) and i) == 0:
                    B[i + p2(j) + p2(k)] = max(B[i + p2(j) + p2(k)],B[i] + B[p2(j) + p2(k)])
            break
    if i mod 10000 == 0:
        echo i
echo B[p2(N) - 1]