/*


weak        weak  we      ak   we  akwea        weak  we
  weak    weak    we      ak   weak    weak    we  ak we
    weakweak      we      ak   wea       ak   we    akwe
      wea         we      ak   we        ak   we    akwe
      wea         we      ak   we        ak   we    akwe
      wea          eak  weak   we        ak    we  ak we
      wea            wea  ak   we        ak     weak  we
                                                      we
we      ak     wea  ak       weak                     we
 we    ak    wea  weak     wea  eak                   we
  we  ak    we      ak   wea      wea         we      we
   weak     we      ak   we        we         we      we
    we      we      ak   we        we         we      we
   we        wea  weak    wea    wea          weak  weak
weak           wea  akw      weak                weak


*/
//#define _GLIBCXX_DEBUG //is only used when couldn't find bug
using namespace std;
#pragma GCC optimize ("Ofast")
/*
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say goodbye
Never gonna tell a lie and hurt you
*/
//headers
#include <vector>
#include <queue>
#include <algorithm>
#include <cmath>
#include <utility>
#include <bitset>
#include <set>
#include <string>
#include <stack>
#include <iomanip>
#include <map>
#include <memory.h>
#include <deque>
#include <time.h>
#include <assert.h>
#include <unordered_map>
#include <unordered_set>
#include <sstream>
#include <random>

//defines
typedef long long LL;
typedef pair<int,int> pii;
typedef pair<LL,LL> pll;
typedef vector<int> vi;
typedef vector<LL> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<LL>> vvl;
#define pb push_back
#define F first
#define S second
#define mid (LB+RB)/2
#define mkp make_pair

//iterators
#define iter(x) x.begin(),x.end()
#define aiter(a,n) a,a+n

//loops
#define REP(n) for (int ___=n > 0 ? n : 0;___--;)
#define REP0(i,n) for (int i=0,___=n;i<___;++i)
#define REP1(i,n) for (int i=1,___=n;i<=___;++i)
#define MEM(e,val) memset (e,val,sizeof(e))

/*
When he said Super Idol的笑容 都没你的甜 八月正午的阳光 都没你耀眼 热爱105℃的你 滴滴清纯的蒸馏水 你不知道你有多可爱 跌倒后会傻笑着再站起来 你从来都不轻言失败 对梦想的执着一直不曾更改 很安心 当你对我说 不怕有我在 放着让我来 勇敢追自己的梦想 那坚定的模样 Super Idol的笑容 都没你的甜 八月正午的阳光 都没你耀眼 热爱105℃的你 滴滴清纯的蒸馏水 在这独一无二 属于我的时代 不怕失败来一场 痛快的热爱 热爱105℃的你 滴滴清纯的蒸馏水 在这独一无二 属于我的时代 莫忘了初心常在 痛快去热爱 爱105℃的你 滴滴清纯的蒸馏水 喝一口又活力全开 再次回到最佳状态 喝一口哟 你不知道你有多可爱 跌倒后会傻笑着再站起来 你从来都不轻言失败 对梦想的执着一直不曾更改 很安心 当你对我说 不怕有我在 放着让我来 勇敢追自己的梦想 那坚定的模样 Super Idol的笑容 都没你的甜 八月正午的阳光 都没你耀眼 热爱105℃的你 滴滴清纯的蒸馏水 在这独一无二 属于我的时代 不怕失败来一场 痛快的热爱 热爱105℃的你 滴滴清纯的蒸馏水 在这独一无二 属于我的时代 莫忘了初心常在 痛快去热爱 热爱105℃的你 滴滴清纯的蒸馏水 喝一口又活力全开 再次回到最佳状态 喝一口又活力全开
I really felt that.


every one is so dian except me
still too weak 咩噗
*/

//IO
#include <cstdio>
#include <iostream>
#include <fstream>
#define want_to_be_more_dian ios_base::sync_with_stdio(false),cin.tie(0);

//pbds
/*
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/priority_queue.hpp>
using namespace __gnu_pbds;
//tree <pii,null_type,less<pii>,rb_tree_tag,tree_order_statistics_node_update>;
*/

//constants
#include <climits>
const int maxn = 230,mod = 0;
const long long INF = LLONG_MAX;
const double eps = 0;

//workspace

#define int LL
struct DIN{
    struct E{
        LL v, c, r;
        E(int v, int c, int r):
            v(v), c(c), r(r){}
    };
    vector<E> adj[maxn];
    void add(int u, int v, int c){
        adj[u].pb(E(v, c, (int) adj[v].size()));
        adj[v].pb(E(u, 0, (int) adj[u].size() - 1));
    }
    int n, s, t;
    void init(int nn, int ss, int tt){
        n = nn, s = ss, t = tt;
        for(int i = 0; i <= n; ++i)
            adj[i].clear();
    }
    int le[maxn], it[maxn];
    int bfs(){
        fill(le, le + maxn, -1); le[s] = 0;
        queue<int> q; q.push(s);
        while(!q.empty()){
            int u = q.front(); q.pop();
            for(auto [v, c, r]: adj[u]){
                if(c > 0 && le[v] == -1)
                    le[v] = le[u] + 1, q.push(v);
            }
        }
        return ~le[t];
    }
    int dfs(int u, int f){
        if(u == t) return f;
        for(int &i = it[u]; i < (int) adj[u].size(); ++i){
            auto &[v, c, r] = adj[u][i];
            if(c > 0 && le[v] == le[u] + 1){
                int d = dfs(v, min(c, f));
                if(d > 0){
                    c -= d;
                    adj[v][r].c += d;
                    return d;
                }
            }
        }
        return 0;
    }
    LL flow(){
        LL ans = 0, d;
        while(bfs()){
            fill(it, it + maxn, 0);
            while((d = dfs(s, INF)) > 0) ans += d;
        }
        return ans;
    }
} din;

int adj[501][501];

inline void solve(){
    int n;

    cin >> n;
    int m = (n+1)/2;
    REP1(i, n) REP1(j, n) cin >> adj[i][j];
    din.init(m * 2+1, 0, m*2+1);
    REP1(i, m){
        din.add(0, i, INF);
        din.add(m+i, m*2+1, INF);
    }
    for (int i=1;i<=n;i+=2){
        din.add(i/2+1, m+1, adj[i][1]);
        for (int j=3;j<n;j+=2){
            din.add(i/2+1, m+j/2+1, adj[j-1][i] + adj[i][j+1]);
        }
        if (n & 1) din.add(i/2+1, m*2, adj[i][n-1]);
    }
    cout << din.flow();
}

signed main(){
    want_to_be_more_dian
    //int t,i=1; for (int ;cin;)//use in multi-testcases and end in EOF problems
    //int t,i=1; for (cin >> t;i<=t;++i)//use in multi-testcases problems
    //cout << "Case #" << i << ": ",//use in Google, FB competitions
    solve();//always used
    return 0;
}