#include <bits/stdc++.h>

#define show(x) cout << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz=" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = 1e9 + 7;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

int n;
unordered_map<int, int> um;
int f[24][24];
int dp(int num)
{
    if (num == 0) {
        return 0;
    }
    if (um.find(num) != um.end()) {
        return um[num];
    }
    bool first = true;
    int fi;
    int s;
    int maxi = -1;
    for (auto i = 0; i < n; i++) {
        if ((num >> i) & 1) {
            if (first) {
                fi = i;
                first = false;
            } else {
                s = i;
                const int ans = dp(num - (1 << fi) - (1 << s)) + f[fi][s];
                maxi = max(maxi, ans);
            }
        }
    }
    um[num] = maxi;
    return maxi;
}

int main()
{
    cin >> n;
    for (auto i = 0; i < n; i++) {
        for (auto j = 0; j < n; j++) {
            cin >> f[i][j];
        }
    }
    const int MAXIMUM = 1 << n;
    cout << dp(MAXIMUM - 1) << endl;

    return 0;
}