#include <iostream>
#include <vector>
#include <utility>
#include <climits>
using namespace std;
/*
2 3
2 7 5
1 9 5
*/
int main() {
int n, m; cin >> n >> m;
vector<vector<int>> nums(n, vector<int>(m));
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
cin >> nums[i][j];
vector<vector<int>> ps(n + 1, vector<int>(m + 1));
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
ps[i + 1][j + 1] = nums[i][j] + ps[i + 1][j] + ps[i][j + 1] - ps[i][j];
vector<vector<vector<vector<int>>>> dp(n, vector<vector<vector<int>>>(m, vector<vector<int>>(n, vector<int>(m))));
for (int a = n - 1; a >= 0; a--) {
for (int b = m - 1; b >= 0; b--) {
for (int c = a; c < n; c++) {
for (int d = b; d < m; d++) {
if (a == c && b == d) continue;
dp[a][b][c][d] = ps[n][m] + 100;
int raisins = ps[c + 1][d + 1] - ps[c + 1][b] - ps[a][d + 1] + ps[a][b];
for (int i = a; i < c; i++)
dp[a][b][c][d] = min(dp[a][b][c][d], raisins + dp[a][b][i][d] + dp[i + 1][b][c][d]);
for (int j = b; j < d; j++)
dp[a][b][c][d] = min(dp[a][b][c][d], raisins + dp[a][b][c][j] + dp[a][j + 1][c][d]);
}
}
}
}
cout << dp[0][0][n - 1][m - 1];
}
