> #include<iostream>
> #include<cstring>
> using namespace std;
> int subset[25];
> int n, G[25][25];
> int ans;
> void dfs(int id, int sum)
> {
>     subset[id] = 1;
>     for(int i = 0; i < n; i++)
>         if(subset[i])
>             sum -= G[id][i];
>         else
>             sum += G[id][i];
>     if(sum > ans)
>         ans = sum;
>     for(int i = id+1; i < n; i++)
>     {
>         dfs(i, sum);
>         subset[i] = 0;
>     }
> }
> int main()
> {
>     cin >> n;
>     for(int i = 0; i < n; i++)
>         for(int j = 0; j < n; j++)
>             cin >> G[i][j];
>     memset(subset, 0, sizeof(subset));
>     ans = 0;
>     dfs(0, 0);
>     cout << ans;
>     return 0;
> }