#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
using namespace atcoder;
int main () {
	int N, M;
	cin >> N >> M;
	std::vector A(N, vector(M, 0ll));
	for (auto& a : A) {
		for (auto& b : a) cin >> b;
	}
	int n = N / 2;
	mcf_graph<ll, ll> gr(2 + n + M + M + n);
	for (int i = 1; i <= n; i ++) {
		gr.add_edge(0, i, 1, 0);
	}
	ll B = (ll)1e9;
	for (int i = 0; i < n; i ++) {
		for (int j = 0; j < M; j ++) {
			gr.add_edge(i+1, j+n+1, 1, A[i][j]);
		}
	}
	for (int j = 0; j < M; j ++) {
		gr.add_edge(j+n+1, j+n+M+1, B, 0);
	}
	for (int i = 0; i < n; i ++) {
		for (int j = 0; j < M; j ++) {
			gr.add_edge(j+n+M+1, i+n+M*2+1, 1, B - A[N-i-1][j]);
		}
	}
	for (int i = 0; i < n; i ++) {
		gr.add_edge(i+n+M*2+1, n*2 + M*2 + 1, 1, 0);
	}
	auto [f, g] = gr.flow(0, n*2 + M*2 + 1);
	assert(f == min(n, M));
	cout << B * f - g << endl;
}