#include <bits/stdc++.h>
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
namespace Flow {
int S, T;
void Set(int _S, int _T) { S = _S, T = _T; }
struct Edge_t {
  int v, nxt, w, cost;
  Edge_t(int V = 0, int Nxt = 0, int W = 0, int Cost = 0) {
    v = V, nxt = Nxt, w = W, cost = Cost;
  }
};
std::vector<Edge_t> e(2);
std::vector<int> head;
void add(int u, int v, int w, int cost) {
  if (u >= (int)head.size()) {
    head.resize(u + 127);
  }
  e.emplace_back(v, head[u], w, cost);
  head[u] = (int)e.size() - 1;
}
void addedge(int u, int v, int w, int cost) {
  add(u, v, w, cost);
  add(v, u, 0, -cost);
}
constexpr int inf = 1e9;
std::queue<int> q;
std::vector<int> dep;
std::vector<int> cur;
std::vector<bool> inq;
bool bfs() {
  dep.assign(head.size(), inf);
  inq.assign(head.size(), false);
  cur = head;
  q.emplace(S), dep[S] = 0;
  while (!q.empty()) {
    int u = q.front(); q.pop(); inq[u] = false;
    for (int i = head[u]; i; i = e[i].nxt) {
      int v = e[i].v;
      if (e[i].w && dep[v] > dep[u] + e[i].cost) {
        dep[v] = dep[u] + e[i].cost;
        if (!inq[v]) {
          inq[v] = true;
          q.emplace(v);
        }
      }
    }
  }
  return dep[T] < inf;
}
int dfs(int u, int flow) {
  if (!flow) {
    return 0;
  } else if (u == T) {
    return flow;
  } else {
    inq[u] = true;
    int f = 0;
    for (int &i = cur[u], rf; i; i = e[i].nxt) {
      int v = e[i].v;
      if (!inq[v] && dep[v] == dep[u] + e[i].cost && (rf = dfs(v, std::min(flow, e[i].w)))) {
        flow -= rf, f += rf;
        e[i].w -= rf, e[i ^ 1].w += rf;
        if (flow == 0) {
          return f;
        }
      }
    }
    return f;
  }
}
std::pair<int, int> dinic() {
  int ans = 0, res = 0;
  while (bfs()) {
    int tmp = dfs(S, inf);
    ans += tmp;
    res += dep[T] * tmp;
  }
  return std::make_pair(ans, res);
}
}
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  int n;
  using namespace std;
  cin >> n;
  int N = (n + 1) / 2;
  int S = N * 2, T = N * 2 + 1;
  Flow::Set(S, T);
  std::vector<vector<int>> a(n, vector<int>(n, 0));
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      cin >> a[i][j];
    }
  }
  for (int i = 0; i < n; i += 2) {
    Flow::addedge(S, i / 2, 1, 0);
    Flow::addedge(i / 2 + N, T, 1, 0);
  }
  for (int i = 0; i < n; i += 2) {
    for (int j = 0; j < n; j += 2) {
      int l = j - 1;
      int r = j + 1;
      int v = 0;
      if (l >= 0) {
        v += a[i][l];
      }
      if (r < n) {
        v += a[i][r];
      }
      Flow::addedge(i / 2, j / 2 + N, 1, v);
    }
  }
  auto tmp = Flow::dinic();
  // std::cout << tmp.first << " " << tmp.second << std::endl;
  cout << tmp.second << "\n";
  return 0;
}