#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 = 1e9; vector<Int> dp(s,-INF); dp[0]=0; for(Int b=0;b<s;b++){ Int u=0; for(Int i=0;i<n;i++) if((~b>>i)&1) u=i; for(Int i=0;i<n;i++) if((~b>>i)&1) if(u!=i) chmax(dp[b|(1<<i)|(1<<u)],dp[b]+f[u][i]); } cout<<dp[s-1]<<endl; return 0; }