#include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(x) cout<<#x" = "<<((x))<<endl
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 21474836

int mat[24][24];
int dp[1<<24];

int main(){
  int n;
  cin>>n;
  rep(i,n) rep(j,n) cin>>mat[i][j];

  fill(dp, dp+(1<<24), -INF);

  dp[0] = 0;

  rep(mask, 1<<n) if(dp[mask]>=0){
    int j =0;
    while( (mask>>j)%2 ) j++;
    for(int k=j+1; k<n; k++) if((mask>>k)%2 == 0){
      int nmask = mask|(1<<j)|(1<<k);
      dp[nmask] = max(dp[nmask], dp[mask] + mat[j][k]);
    }
  }

  cout << dp[(1<<n)-1] << endl;

  return 0;
}