#define mul_cases false

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cctype>
#include <vector>
#include <cstring>
#include <queue>
#define int long long
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

bool MEM1;

const int buf_siz = 1 << 12;

char inbuf[buf_siz], *p1, *p2;

inline char gc()
{
    if (p1 == p2)
        p1 = inbuf, p2 = p1 + fread(inbuf, 1, buf_siz, stdin);
    return p1 == p2 ? EOF : *p1++;
}

int read()
{
    int x = 0, f = 1;
    char ch = gc();
    for (; !isdigit(ch); ch = gc())
        if (ch == '-')
            f = -1;
    for (; isdigit(ch); ch = gc())
        x = x * 10 + ch - '0';
    return x * f;
}

namespace solve
{
    const int maxn = 1010;
    const int inf = 1e9;

    struct Dinic
    {
        struct edge
        {
            int x, y, cap, flow, cost;
        };
        vector<edge> edges;
        vector<int> e[maxn];

        inline void add(int x, int y, int cap, int cost)
        {
            // cerr << x << " " << y << " " << cap << " " << cost << endl;
            edges.push_back({x, y, cap, 0, cost});
            edges.push_back({y, x, 0, 0, -cost});
            int m = edges.size();
            e[x].push_back(m - 2), e[y].push_back(m - 1);
        }
        ll dis[maxn];
        int vis[maxn], cur[maxn], s, t;

        bool spfa()
        {
            queue<int> q;
            memset(dis, 0x3f, sizeof(int) * (t + 2)), memset(vis, 0, sizeof(int) * (t + 2));
            dis[s] = 0, vis[s] = 1, q.push(s);
            while (!q.empty())
            {
                int x = q.front();
                q.pop(), vis[x] = 0;
                for (int i : e[x])
                {
                    auto &k = edges[i];
                    if (k.cap - k.flow > 0 && k.cost + dis[x] < dis[k.y])
                    {
                        dis[k.y] = dis[x] + k.cost;
                        if (!vis[k.y])
                            q.push(k.y), vis[k.y] = 1;
                    }
                }
            }
            return dis[t] < 1e8;
        }

        ll mcmf;

        int dfs(int x, int lim)
        {
            if (x == t || lim == 0)
                return lim;
            vis[x] = 1;
            int res = 0, f;
            for (int &i = cur[x]; i < (int)e[x].size(); i++)
            {
                auto &k = edges[e[x][i]];
                if (dis[x] + k.cost != dis[k.y] || vis[k.y] || (f = dfs(k.y, min(lim, k.cap - k.flow))) == 0)
                    continue;
                mcmf += 1ll * f * k.cost;
                k.flow += f, edges[e[x][i] ^ 1].flow -= f, res += f, lim -= f;
                if (lim == 0)
                    break;
            }
            vis[x] = 0;
            return res;
        }

        ll dinic(int s_, int t_)
        {
            s = s_, t = t_;
            mcmf = 0;
            int ans = 0;
            while (spfa())
                memset(cur, 0, sizeof(int) * (t + 2)), ans += dfs(s, 1 << 25);
            return mcmf;
        }
    } G;
    
    int e[maxn][maxn], n;

    void main()
    {
        n = read();
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
                e[i][j] = read();
        int R = n / 2, L = n - R;
        R = L;
        int S = L + R + 1, T = S + 1;
        for (int i = 1; i <= L; i++)
            G.add(S, i, 1, 0);
        for (int i = 1; i <= R; i++)
            G.add(i + L, T, 1, 0);
        for (int i = 1; i <= L; i++)
        {
            for (int j = 1; j <= R; j++)
            {
                int x = (i - 1) * 2 + 1;
                int y = (j - 1) * 2 + 1;
                G.add(i, j + L, 1, e[x][y - 1] + e[x][y + 1]);
            }
        }
        cout << G.dinic(S, T) << endl;
    }
}


bool MEM2;

signed main()
{
#ifdef local
    cerr << "memory : " << abs(&MEM1 - &MEM2) / 1024. / 1024 << " mb" << endl;
#endif

    int cases = 1;

    if (mul_cases)
        cin >> cases;

    while (cases--)
        solve::main();

#ifdef local
    cerr << "time : " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms" << endl;
#endif

    return 0;
}