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
	mi1 = -1
	mi2 = -1
	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
			if mi1 == - 1 or mi2 == -2 or f[mi1][mi2] < f[i][j]:
				mi1 = i
				mi2 = j
	ret = dfs(S | 1 << mi1 | 1 << mi2) + f[mi1][mi2]
	dp[S] = ret
	return ret
print(dfs(0))