// Muallif: Azimjon Mehmonali o'g'li
#include <bits/stdc++.h>
using namespace std;
#define int long long
const long double PI = 3.1415926535897;
const int mod = 1000000007LL;
const int INF = 1e18;
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
vector<vector<int>> g(n, vector<int>(m));
vector<int> sy;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> g[i][j];
}
sy.push_back(accumulate(g[i].begin(), g[i].end(), 0));
}
vector<vector<int>> dp(n, vector<int>(n, INF));
function<int(int, int)> dfs = [&](int l, int r) {
if (l == r) return 0ll;
if (dp[l][r] != INF) return dp[l][r];
int yi = 0, py = 0;
for (int i = l; i <= r; i++)
yi += sy[i];
int x = INF;
vector<int> v;
for (int i = l; i <= r; i++) {
py += sy[i];
if (py > yi - py) {
v.push_back(i);
v.push_back(i - 1);
break;
}
}
for (int i : v) {
// cerr << i << endl;
if (i < l || r < i + 1) continue;
x = min(x, dfs(l, i) + dfs(i + 1, r));
}
return x + yi;
};
int nt = dfs(0, n - 1);
// cerr << nt << endl;
for (int i = 0; i < n; i++) {
dp.assign(m, vector<int>(m, INF));
sy = g[i];
nt += dfs(0, m - 1);
}
cout << nt << endl;
return 0;
}
