#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  Int f[30][30];
  for(Int i=0;i<n;i++)
    for(Int j=0;j<n;j++)
      cin>>f[i][j];

  Int s=1<<n;
  const Int INF = 1e15;
  vector<Int> dp(s,-INF);
  dp[0]=0;
  for(Int b=0;b<s;b++){
    if(dp[b]<0) continue;
    Int u=0;
    for(Int i=0;i<n;i++)
      if((~b>>i)&1) u=i;
    for(Int i=0;i<u;i++)
      if((~b>>i)&1) chmax(dp[b|(1<<i)|(1<<u)],dp[b]+f[u][i]);
  }

  Int ans=dp[s-1];
  cout<<ans<<endl;
  return 0;
}