#include <cstdio>
#include <algorithm>

using namespace std;

const int MAX = 24;
int N;
int f[MAX][MAX];
int dp[1 << MAX];

int main(int argc, char** argv) {
    scanf("%d", &N);
    for (size_t i = 0; i < N; i++) {
        for (size_t j = 0; j < N; j++) {
            scanf("%d", f[i] + j);
        }
    }
    for (int i = 0; i < (1 << N); i++) {
        if ((__builtin_popcount(i) & 1) == 0 && __builtin_popcount(i) < N) {
            for (int j = 0; j < N; j++) {
                if ((i & (1 << j)) == 0) {
                    for (int k = j + 1; k < N; k++) {
                        if ((i & (1 << k)) == 0) {
                            dp[i | (1 << j) | (1 << k)] = max(dp[i | (1 << j) | (1 << k)], dp[i] + f[j][k]);
                        }
                    }
                }
            }
        }
    }
    printf("%d\n", dp[(1 << N) - 1]);
}