#include<bits/stdc++.h>
#define int long long
using namespace std;
int a[30][30],dp[20000010];
bool f[20000010];
queue<int> q;
signed main()
{
	int n,x,i;
	cin>>n;
	for(i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
			cin>>a[i][j];
	}
	q.push(0);
	while(!q.empty())
	{
		x=q.front();
		f[x]=0;
		q.pop();
		i=0;
		for(;i<=n;i++)
		{
			if(((1<<i)&x)==0)
				break;
		}
		i++;
		for(int j=i+1;j<=n;j++)
		{
			if((x|(1<<(j-1)))==x)
				continue;
			int k=x|(1<<(i-1))|(1<<(j-1));
			if(f[k]&&dp[x]+a[i][j]>dp[k])
				dp[k]=dp[x]+a[i][j];
			else if(!f[k])
			{
				f[k]=1;
				dp[k]=dp[x]+a[i][j];
				q.push(k);
			}
		}
	}
	cout<<dp[(1<<(n))-1];
	return 0;
}