#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <stack>
#include <queue>
#include <functional>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <vector>
#include <array>
#include <tuple>
#include <utility>
#include <numeric>
#include <iomanip>
#include <cctype>
#include <cmath>
#include <assert.h>
#include <cstdlib>
#include <list>
using namespace std;

using ll = long long;
using ull = unsigned long long;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;

template<typename T1, typename T2> ostream& operator<<(ostream& s, const pair<T1, T2>& p) {
    return s << "(" << p.first << ", " << p.second << ")";
}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& v) {
    s << "[";
    for (int i = 0; i < v.size(); i++) s << (i == 0 ? "" : ", ") << v[i];
    s << "]";
    return s;
}

#define ALL(a) (a).begin(), (a).end()

int size[1 << 24], dp[1 << 24], cost[1 << 24];
int table[24][24];

int main() {
    int n;
    cin >> n;
    for (int r = 0; r < n; r++) {
        for (int c = 0; c < n; c++) {
            cin >> table[r][c];
        }
    }
    for (int mask = 0; mask < (1 << n); mask++) {
        for (int i = 0; i < n; i++) {
            if ((mask >> i) & 1) size[mask]++;
        }
    }

    vector<PII> foo;
    for (int a = 0; a < n; a++) {
        for (int b = a + 1; b < n; b++) {
            cost[(1 << a) | (1 << b)] = table[a][b];
            foo.push_back(make_pair((1 << a) | (1 << b), table[a][b]));
        }
    }

    memset(dp, -1, sizeof(dp));
    dp[(1 << n) - 1] = 0;
    for (int mask = (1 << n) - 1; mask > 0; mask--) {
        if (dp[mask] < 0 || size[mask] % 2 == 1) continue;

        for (PII& f : foo) {
            if ((mask & f.first) == f.first) {
                dp[mask ^ f.first] = max(dp[mask ^ f.first], dp[mask] + f.second);
            }
        }
    }
    cout << dp[0] << endl;

    return 0;
}