#include "bits/stdc++.h" 
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) FOR(i, 0, n)
template<class T> bool checkmax(T &a, T b) { return b > a ? a = b, 1 : 0; }

int N;
int table[20][20];
int dp[1 << 20];

void solve() {
    for (int mask = 2; mask < (1 << N); mask++)
    {
        int tmpMask = mask;
        for (; tmpMask != 0; )
        {
            int a = __builtin_ctz(tmpMask);
            tmpMask -= 1 << a;
            int tmpMask2 = tmpMask;
            for (; tmpMask2 != 0; )
            {
                int b = __builtin_ctz(tmpMask2);
                tmpMask2 -= 1 << b;
                checkmax(dp[mask], dp[mask ^ 1 << a ^ 1 << b] + table[a][b]);
            }
        }
    }
    cout << dp[(1 << N) - 1] << endl;
}

int main() {
    cin >> N;
    rep(a, N) rep(b, N) cin >> table[a][b];
    solve();
    return 0;
}