#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for (auto i = a; i < (b); ++i)
#define repr(i, a, b) for (auto i = (a) - 1; i >= (b); --i)
#define pb push_back
#define eb emplace_back
#define all(x) begin(x), end(x)
#define sz(x) int((x).size())

using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<pii>;

template<class T>
inline bool cmax(T &a, const T &b) {
    return a < b ? a = b, 1 : 0;
}

template<class T>
inline bool cmin(T &a, const T &b) {
    return b < a ? a = b, 1 : 0;
}

const int inf = 0x3f3f3f3f;
const ll linf = 1e18;
const double dinf = numeric_limits<double>::infinity();
const int maxn = 1005;
int c[maxn][maxn];
int n;
int m;

int randInt (int b) {
    return rand()%b+1;
}
double rand01 () {
    return (double)rand()/RAND_MAX;  
}

int set1[maxn]; // +ve
int set2[maxn]; // -ve
int sum;
int ans;

void SA () {
    double T = 300;
    const int REP = 1e4;
    for (int t=1;t<=REP;t++) {
        int a = randInt(m);
        int b = randInt(m);
        int delta = 0;
        for (int i=1;i<=m;i++) {
            if (i == a) continue;
            delta -= c[set1[i]][set1[a]];
        }
        for (int i=1;i<=m;i++) {
            if (i == b) continue;
            delta += c[set2[i]][set2[b]];
        }
        for (int i=1;i<=m;i++) {
            if (i == a) continue;
            delta += c[set1[i]][set2[b]];
        }
        for (int i=1;i<=m;i++) {
            if (i == b) continue;
            delta -= c[set2[i]][set1[a]];
        }
        // cout << set1[a] << set2[b] << endl;
        // cout << delta << endl;
        if (delta > 0 && exp(-delta/T) <= rand01()) {
            // cout << "det " << delta;
            // cout << exp(-delta/T) << endl;
            swap(set1[a], set2[b]);
            sum += delta;
            ans = max(ans, sum);
            T *= 0.997;
        }
    }
}
int main() {
    srand(time(0));
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    cin >> n;
    for (int i=1;i<=n;i++) for (int j=1;j<=n;j++) {
        cin >> c[i][j];
    }
    m = n/2;
    for (int i=1;i<=m;i++) {
        set1[i] = i;
        for (int j=1;j<i;j++) {
            sum += c[i][j];
        }
    }
    for (int i=m+1;i<=m+m;i++) {
        set2[i-m] = i;
        for (int j=m+1;j<i;j++) {
            sum -= c[i][j];
        }
    }
    ans = sum; 
    SA();
    cout << ans << endl;
    return 0;
}
/*
4
0 1 2 2
1 0 8 -3
2 8 0 5
2 -3 5 0
6

6
0 4 -6 2 3 -3
4 0 2 -6 0 0
-6 2 0 0 2 2
2 -6 0 0 -1 5
3 0 2 -1 0 -4
-3 0 2 5 -4 0
0
*/