#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<ll, ll>;
#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
template<typename T> void chmin(T &a, const T &b) { a = min(a, b); }
template<typename T> void chmax(T &a, const T &b) { a = max(a, b); }
struct FastIO {FastIO() { cin.tie(0); ios::sync_with_stdio(0); }}fastiofastio;
#ifdef DEBUG_ 
#include "../program_contest_library/memo/dump.hpp"
#else
#define dump(...)
#endif
const ll INF = 1LL<<60;

ll n, f[24][24];
ll dfs(ll idx, ll num, vector<int> used) {
    if(idx == n) {
        if(num*2 == n) return 0;
        return -INF;
    }
    ll ret = dfs(idx+1, num, used);
    REP(i, n) {
        if(used[i]==1 || used[idx]==1 || idx == i) continue;
        used[idx] = used[i] = 1;
        num++;
        chmax(ret, dfs(idx+1, num, used) + f[idx][i]);
        used[idx] = used[i] = 0;
        num--; 
    }
    return ret;
}

int main(void) {
    cin >> n;
    REP(i, n) REP(j, n) cin >> f[i][j];

    vector<int> used(n, 0);
    cout << dfs(0, 0, used) << endl;

    return 0;
}