#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>

#include <functional>
#include <cassert>

typedef long long ll;
using namespace std;

#define debug(x) cerr << #x << " = " << (x) << endl;


#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 30

int dp[1<<24];

int main(){
  int n;
  int f[SIZE][SIZE];
  scanf("%d",&n);

  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      scanf("%d",f[i]+j);
    }
  }

  for(int i=0;i<(1<<n)-1;i++){
    dp[i] = -INF;
  }
  dp[0] = 0;
  
  for(int i=0;i<(1<<n)-1;i++){
    
    if((dp[i]<0 && i != 0)) continue;
    
    for(int j=0;j<n;j++){
      if((1<<j) & i) continue;
      for(int k=j+1;k<n;k++){
        if((1<<k) & i) continue;
        
        dp[i | (1<<j) | (1<<k)] = max(dp[i | (1<<j) | (1<<k)], dp[i] + f[j][k]);
        
      }
      break;
    }
    
  }
  
  printf("%d\n",dp[(1<<n)-1]);
  
  return 0;
}