#include <bits/stdc++.h>
using namespace std;

#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define bit(n) (1LL<<(n))
#define sz(x) ((int)(x).size())
#define fst first
#define snd second

#define _TMPL_OVERLOAD(_1,_2,name,...) name
#define _TMPL1(T) template<class T>
#define _TMPL2(T,U) template<class T,class U>
#define TMPL(...) _TMPL_OVERLOAD(__VA_ARGS__,_TMPL2,_TMPL1)(__VA_ARGS__)
string DBG_DLM(int &i){return(i++==0?"":", ");}
#define DBG_B(exp){int i=0;os<<"{";{exp;}os<<"}";return os;}
TMPL(T)ostream&operator<<(ostream&os,vector<T>v);
TMPL(T)ostream&operator<<(ostream&os,set<T>v);
TMPL(T)ostream&operator<<(ostream&os,queue<T>q);
TMPL(T)ostream&operator<<(ostream&os,priority_queue<T>q);
TMPL(T,K)ostream&operator<<(ostream&os,pair<T,K>p);
TMPL(T,K)ostream&operator<<(ostream&os,map<T,K>mp);
TMPL(T,K)ostream&operator<<(ostream&os,unordered_map<T,K>mp);
template<int I,class TPL>void DBG(ostream&os,TPL t){}
template<int I,class TPL,class H,class...Ts>void DBG(ostream&os,TPL t){os<<(I==0?"":", ")<<get<I>(t);DBG<I+1,TPL,Ts...>(os,t);}
TMPL(T,K)void DBG(ostream&os,pair<T,K>p,string delim){os<<"("<<p.first<<delim<<p.second<<")";}
TMPL(...Ts)ostream&operator<<(ostream&os,tuple<Ts...>t){os<<"(";DBG<0,tuple<Ts...>,Ts...>(os,t);os<<")";return os;}
TMPL(T,K)ostream&operator<<(ostream&os,pair<T,K>p){DBG(os,p,", ");return os;}
TMPL(T)ostream&operator<<(ostream&os,vector<T>v){DBG_B(forr(t,v){os<<DBG_DLM(i)<<t;});}
TMPL(T)ostream&operator<<(ostream&os,set<T>s){DBG_B(forr(t,s){os<<DBG_DLM(i)<<t;});}
TMPL(T)ostream&operator<<(ostream&os,queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.front();});}
TMPL(T)ostream&operator<<(ostream&os,priority_queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.top();});}
TMPL(T,K)ostream&operator<<(ostream&os,map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
TMPL(T,K)ostream&operator<<(ostream&os,unordered_map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
#define DBG_OVERLOAD(_1,_2,_3,_4,_5,_6,macro_name,...)macro_name
#define DBG_LINE(){char s[99];sprintf(s,"line:%3d | ",__LINE__);cerr<<s;}
#define DBG_OUTPUT(v){cerr<<(#v)<<"="<<(v);}
#define DBG1(v,...){DBG_OUTPUT(v);}
#define DBG2(v,...){DBG_OUTPUT(v);cerr<<", ";DBG1(__VA_ARGS__);}
#define DBG3(v,...){DBG_OUTPUT(v);cerr<<", ";DBG2(__VA_ARGS__);}
#define DBG4(v,...){DBG_OUTPUT(v);cerr<<", ";DBG3(__VA_ARGS__);}
#define DBG5(v,...){DBG_OUTPUT(v);cerr<<", ";DBG4(__VA_ARGS__);}
#define DBG6(v,...){DBG_OUTPUT(v);cerr<<", ";DBG5(__VA_ARGS__);}
#define DEBUG0(){DBG_LINE();cerr<<endl;}
#ifdef LOCAL
#define out(...){DBG_LINE();DBG_OVERLOAD(__VA_ARGS__,DBG6,DBG5,DBG4,DBG3,DBG2,DBG1)(__VA_ARGS__);cerr<<endl;}
#else
#define out(...)
#endif

TMPL(T,K)istream&operator>>(istream&is,pair<T,K>&p){is>>p.fst;is>>p.snd;return is;}
TMPL(T)istream&operator>>(istream&is,vector<T>&v){forr(e,v)is>>e;return is;}
#define rea(type, ...)type __VA_ARGS__;MACRO_VAR_Scan(__VA_ARGS__);
TMPL(T)void MACRO_VAR_Scan(T&t){cin>>t;}
TMPL(H,...Ts)void MACRO_VAR_Scan(H&h,Ts&...ts) {cin>>h;MACRO_VAR_Scan(ts...);}
#define rea_vecs(type,n,...)vector<type> __VA_ARGS__;MACRO_VEC_ROW_Init(n,__VA_ARGS__);rep(i,n)MACRO_VEC_ROW_Scan(i,__VA_ARGS__);
TMPL(T)void MACRO_VEC_ROW_Init(int n, T& t) { t.resize(n); }
TMPL(H,...Ts)void MACRO_VEC_ROW_Init(int n,H&h,Ts&...ts){h.resize(n);MACRO_VEC_ROW_Init(n,ts...);}
TMPL(T)void MACRO_VEC_ROW_Scan(int p,T&t){cin>>t[p];}
TMPL(H,...Ts)void MACRO_VEC_ROW_Scan(int p,H&h,Ts&...ts){cin>>h[p];MACRO_VEC_ROW_Scan(p,ts...);}
#define rea_vec(type,n,c) vector<type>c(n);cin>>c;

//#define int long long  // consider risk of MLE
using ll=long long;
using pii=pair<int,int>;using pll=pair<ll,ll>;using pil=pair<int,ll>;using pli=pair<ll,int>;
using vs=vector<string>;using vvs=vector<vs>;using vvvs=vector<vvs>;
using vb=vector<bool>;using vvb=vector<vb>;using vvvb=vector<vvb>;
using vi=vector<int>;using vvi=vector<vi>;using vvvi=vector<vvi>;
using vl=vector<ll>;using vvl=vector<vl>;using vvvl=vector<vvl>;
using vd=vector<double>;using vvd=vector<vd>;using vvvd=vector<vvd>;
using vpii=vector<pii>;using vvpii=vector<vpii>;using vvvpii=vector<vvpii>;
template<class T>bool amax(T&a,T&b){return a<b?a=b,1:0;}
template<class T>bool amin(T&a,T&b){return a>b?a=b,1:0;}
ll ri(){ll l;cin>>l;return l;} string rs(){string s;cin>>s;return s;}
template<class T>T read(){T t;cin>>t;return t;}

class Dinic {
  const int INF = 2e9;
  // 行き先、容量、逆辺のインデックス
  struct edge { int to, cap, rev; };

  public:
  int V;
  vector<vector<edge>> G;
  vector<int> level, iter;
  Dinic(int V) : V(V), G(V), level(V), iter(V) {}

  // fromからtoへ向かう容量capの辺をグラフに追加する
  void add_edge(int from, int to, int cap) {
    G[from].push_back((edge){to, cap, (int) G[to].size()});
    G[to].push_back((edge){from, 0, (int) G[from].size() - 1});
  }

  private:
  // sからの最短距離をBFSで算する
  void bfs(int s) {
    fill(level.begin(), level.end(), -1);
    level[s] = 0;
    queue<int> q;
    q.push(s);
    while (!q.empty()) {
      int v = q.front();
      q.pop();
      for (int i = 0; i < (int) G[v].size(); i++) {
        edge &e = G[v][i];
        if (e.cap > 0 && level[e.to] < 0) {
          level[e.to] = level[v] + 1;
          q.push(e.to);
        }
      }
    }
  }

  // 増加パスをDFSで探す
  int dfs(int v, int t, int f) {
    if (v == t) return f;
    for (int &i = iter[v]; i < (int) G[v].size(); i++) {
      edge &e = G[v][i];
      if (e.cap > 0 && level[v] < level[e.to]) {
        int d = dfs(e.to, t, min(f, e.cap));
        if (d > 0) {
          e.cap -= d;
          G[e.to][e.rev].cap += d;
          return d;
        }
      }
    }
    return 0;
  }

  public:
  // sからtへの最大流を求める
  int max_flow(int s, int t) {
    int flow = 0;
    for (;;) {
      bfs(s);
      if (level[t] < 0) return flow;
      fill(iter.begin(), iter.end(), 0);
      int f;
      while ((f = dfs(s, t, INF)) > 0) {
        flow += f;
      }
    }
  }
};

ll solve() {
  rea(int, n);

  vvi A(n, vi(n));

  rep(i, n) {
    rep(j, n) {
      A[i][j] = ri();
    }
  }

  // bitdp...

  vi dp(bit(n));

  rep(i, bit(n)) {
    rep(j, n) if ((i & bit(j)) == 0) {
      rep(k, j+1, n) if ((i & bit(k)) == 0) {
        dp[i | bit(j) | bit(k)] = max(dp[i | bit(j) | bit(k)], dp[i] + A[j][k]);
      }
    }
  }

  return dp[bit(n)-1];
}

void Main() {
  cout << solve() << endl;
}

signed main() { cin.tie(nullptr); ios::sync_with_stdio(false); Main(); return 0; }