#include <iostream>
#include <vector>
#include <algorithm>
#include <array>
#include <numeric>
#include <functional>

using namespace std;

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int nl; cin >> nl;
	vector<vector<int64_t>> pl(nl, vector<int64_t>(nl));
	for (int i = 0; i < nl; ++i) {
		for (int j = 0; j < nl; ++j) {
			cin >> pl[i][j];
		}
	}
	
	int n = (nl + 1) / 2;
	vector<vector<int64_t>> c(n, vector<int64_t>(n, 0));
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) {
			if (2*j > 0) c[i][j] += pl[2*i][2*j-1];
			if (2*j < nl-1) c[i][j] += pl[2*i][2*j+1];
		}
	}

	vector<int64_t> wx(n, 2e9), wy(n, 0), slk(n);
	vector<int> mx(n, -1), my(n, -1), vis(n), par(n), q;

	const auto bfs = [&](int s) {
		fill(slk.begin(), slk.end(), 2e9);
		fill(vis.begin(), vis.end(), 0);
		q.clear();
		vis[s] = 1;
		q.push_back(s);
		int qi = 0;

		while (true) {
			for (; qi < (int) q.size(); ++qi) {
				int x = q[qi];
				for (int y = 0; y < n; ++y) if (my[y] == -1 or !vis[my[y]]) {
					int64_t k = wx[x] + wy[y] - c[x][y];
					if (k == 0) {
						par[y] = x;
						if (my[y] == -1) {
							for (int i = y; i != -1; swap(mx[my[i] = par[i]], i));
							return;
						} else {
							vis[my[y]] = 1;
							q.push_back(my[y]);
						}
					} else if (slk[y] > k) {
						par[y] = x;
						slk[y] = k;
					}
				}
			}

			int y = -1; int64_t minslk = 2e9;
			for (int i = 0; i < n; ++i) if (my[i] == -1 or !vis[my[i]]) {
				if (slk[i] < minslk) minslk = slk[y = i];
			}
			for (int x = 0; x < n; ++x) if (vis[x]) {
				wx[x] -= minslk;
				if (mx[x] != -1) wy[mx[x]] += minslk;
			}
			if (my[y] == -1) {
				for (int i = y; i != -1; swap(mx[my[i] = par[i]], i));
				return;
			} else {
				vis[my[y]] = 1;
				q.push_back(my[y]);
			}
		}
	};

	for (int s = 0; s < n; ++s) bfs(s);
	cout << accumulate(wx.begin(), wx.end(), accumulate(wy.begin(), wy.end(), int64_t(0))) << endl;
	return 0;
}