def solve():
  def rec(s, memo={0: 0}):
    if not s in memo:
      i = (s & -s).bit_length() - 1
      u = t = s & (s - 1)
      best = 0
      while t:
        f = t & -t
        j = f.bit_length() - 1
        best = max(best, rec(u ^ f) + cost[i][j])
        t ^= f
      memo[s] = best
    return memo[s]
  N = int(raw_input())
  cost = [list(map(int, raw_input().split())) for _ in range(N)]
  print(rec(2 ** N - 1))

solve()