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

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i >= (a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 1 << 10;

LL c[N][N];
LL cost[N];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    FOR(i, 0, n)
    FOR(j, 0, n)
    cin >> c[i][j];

    LL D = 0;
    FOR(i, 0, n)
    FOR(j, 0, n)
    D += c[i][j];

    FOR(i, 0, n)
    {
        FOR(j, 0, n)
        cost[i] -= c[i][j];

        // cout << cost[i] << endl;
    }
    D /= 2;
    // cout << D << endl;

    VI isL(n, 0);
    FOR(i, 0, n / 2)
    {
        int v = -1;
        FOR(u, 0, n)
        {
            if (isL[u])
                continue;
            if (v == -1 || cost[u] > cost[v])
                v = u;
        }
        // cout << v << " " << cost[v] << endl;
        D += cost[v];

        isL[v] = 1;
    }
    cout << D << endl;

    return 0;
}