#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;

int dp[1 << 24];

int main() {
    int N;
    cin >> N;
    int A[N][N];
    rep(i, N) rep(j, N) cin >> A[i][j];
    rep(i, 1 << N) dp[i] = -2e9;
    rep(k, N / 2) {
        if (k == 0) {
            for(int i = 1; i < N; i++) dp[1 | 1 << i] = A[0][i];
            continue;
        }
        int s = (1 << k) - 1;
        int x, y;
        for (int T = (1 << k) - 1; T < (1 << N - k); x = T & -T, y = T + x, T = (((T & ~y) / x) >> 1) | y) {
            int mask = s | T << k;
            int i = 0;
            while(mask & 1 << i) i++;
            for(int j = i + 1; j < N; ++j) {
                if (mask & 1 << j) continue;
                int nmask = mask | 1 << i | 1 << j;
                dp[nmask] = max(dp[nmask], dp[mask] + A[i][j]);
            }
        }
    }
    cout << dp[(1 << N) - 1] << endl;
}