#include<bits/stdc++.h>
//#define int long long
//#define eps 1e-9
//#define ENF 1e13
using namespace std;
inline int read()
{
  int x=0,f=1;char ch=getchar();
  while (ch<'0'||ch>'9'){if (ch=='-') f=-1;ch=getchar();}
  while (ch>='0'&&ch<='9'){x=(x<<3)+(x<<1)+ch-48;ch=getchar();}
  return x*f;
}
void write(int x)
{
  if(x<0)putchar('-'),x=-x;
  if(x<10)putchar(x+'0');
  else write(x/10),putchar(x%10+'0');
}
const int N=30;
const int mod=1e9+7;
int n;
int a[N][N];
int dp[1<<(28)];
int cal(int z){
	int sum=0;
	while(z){
		if(z&1)sum++;
		z>>=1;
	}
	return sum;
}
signed main(){
	n=read();
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			a[i][j]=read();
		int zz=0;
	for(int i=0;i<(1<<n);i++){
//		if(__builtin_popcount(i)&1==1)continue;
//		for(int j=1;j<=n;j++){
//			if(i&(1<<(j-1)))continue;
//			for(int k=j+1;k<=n;k++){ 
//				if(i&(1<<(k-1)))continue;
//			//	zz++;
//				dp[(i|(1<<(j-1)))|(1<<(k-1))]=max(dp[i]+a[j][k],dp[(i|(1<<(j-1)))|(1<<(k-1))]);
//			}	
//		}
	}
	//cout<<zz<<"?\n";
	cout<<dp[(1<<n)-1]<<"\n";
   return 0;
}