#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FOR(i, a, b) for (int i = (a); i < int(b); ++i)
#define RFOR(i, a, b) for (int i = (b)-1; i >= int(a); --i)
#define rep(i, n) FOR(i, 0, n)
#define rep1(i, n) FOR(i, 1, int(n) + 1)
#define rrep(i, n) RFOR(i, 0, n)
#define rrep1(i, n) RFOR(i, 1, int(n) + 1)
#define all(c) begin(c), end(c)
const int MOD = 1000000007;

template <typename T>
void __dump__(std::ostream &os, const T &first) {
    os << first;
}
template <typename First, typename... Rest>
void __dump__(std::ostream &os, const First &first, const Rest &... rest) {
    os << first << ", ";
    __dump__(os, rest...);
}
#define dump(...)                                         \
    do {                                                  \
        std::ostringstream os;                            \
        os << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; \
        __dump__(os, __VA_ARGS__);                        \
        std::cerr << os.str() << std::endl;               \
    } while (0)

int dp[1<<24];
int f[24][24];
int n;

// int rec(int S) {
//     int &res = dp[S];
//     if (res != -1) return res;
//     if (S + 1 == 1 << n) {
//         res = 0;
//     } else {
//         rep(i, n) rep(j, n) {
//             if(i == j || S >> i & 1 || S >> j & 1) continue;
//             int cand = rec(S | 1 << i | 1 << j) + f[i][j];
//             res = max(res, cand);
//         }
//     }
//     return res;
// }

int main() {
    while (cin >> n) {
        memset(dp, -1, sizeof dp);
        rep(i, n) rep(j, n) cin >> f[i][j];
        dp[0] = 0;
        rep(S, 1<<n) {
            rep(i, n) rep(j, n) {
                if (i == j || S >> i & 1 || S >> j & 1) continue;
                int cand = f[i][j] + dp[S];
                int nS = S|1<<i|1<<j;
                dp[nS] = max(dp[nS], cand);
            }
        }
        cout << dp[(1 << n) - 1] << endl;
    }
}