#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
using namespace std;
#define all(a) (a).begin(), (a).end()
#define sz(a) (int)(a).size()
#define ll long long
#define ld long double
#define ui uint64_t
#define cont(set, element) ((set).find(element) != (set).end())
/********* DEBUG *********/
template <typename T>
void outvec(const vector<T>& Z){
for (const T& x : Z)
cout << x << ' ';
cout << "\n";
}
void printVariable(const any& var) {
if (!var.has_value()) {
cout << "null";
return;
}
if (var.type() == typeid(int)) {
cout << any_cast<int>(var);
} else if (var.type() == typeid(double)) {
cout << any_cast<double>(var);
} else if (var.type() == typeid(float)) {
cout << any_cast<float>(var);
} else if (var.type() == typeid(char)) {
cout << any_cast<char>(var);
} else if (var.type() == typeid(bool)) {
cout << (any_cast<bool>(var) ? "true" : "false");
} else if (var.type() == typeid(string)) {
cout << any_cast<string>(var);
} else if (var.type() == typeid(const char*)) {
cout << any_cast<const char*>(var);
} else if (var.type() == typeid(long long)) {
cout << any_cast<long long>(var);
} else {
cout << "[unknown type]";
}
}
template<typename... Args>
void outval(Args... args) {
vector<any> variables = {args...};
for (size_t i = 0; i < variables.size(); ++i) {
printVariable(variables[i]);
if (i != variables.size() - 1) {
cout << " ";
}
}
cout << "\n";
}
#define sp << " " <<
/********* DEBUG *********/
const ll MOD = 1e9+7;
const ll MOD2 = 998244353;
const ll inf = 1e18;
const ll mxN = 2000005;
ll re(ll tlx, ll tly, ll brx, ll bry, vector<vector<ll>> &grid, ll sum){
ll ans = inf;
if (tlx == brx && tly == bry)
return 0;
ll curr = 0;
for (int i = tly; i < bry; i++){
for (int j = tlx; j <= brx; j++){
curr += grid[i][j];
}
ans = min(ans, re(tlx, tly, brx, i, grid, curr) + re(tlx, i + 1, brx, bry, grid, sum-curr));
}
curr = 0;
for (int i = tlx; i < brx; i++){
for (int j = tly; j <= bry; j++)
curr += grid[j][i];
ans = min(ans, re(tlx, tly, i, bry, grid, curr) + re(i + 1, tly, brx, bry, grid, sum-curr));
}
return ans + sum;
}
void solve(){
ll n,m;
cin >> n >> m;
vector<vector<ll>> grid(n,vector<ll>(m));
ll sum = 0;
for (int i = 0; i < n; i++){
for (int j = 0; j < m; j++){
cin >> grid[i][j];
sum += grid[i][j];
}
}
outval(re(0, 0, m-1, n-1, grid, sum));
}
int main() {
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios::sync_with_stdio(0);
cin.tie(0);
ll t = 1;
//cin >> t;
while (t--) {
solve();
}
}
