#include <bits/stdc++.h>
using namespace std;
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
 
    int n, m;
    cin >> n >> m;
    vector<vector<int>> a(n, vector<int>(m));
    for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
            cin >> a[i][j];
 
    long long ans = LLONG_MIN;
 
    // chọn hàng trên x
    for(int x = 0; x < n; x++){
        vector<int> colSum(m, 0);  // V[i]
 
        // chọn hàng dưới u
        for(int u = x + 1; u < n; u++){
            // cập nhật V[i] += a[u-1][i]
            for(int c = 0; c < m; c++)
                colSum[c] += (u - x > 1 ? a[u-1][c] : 0);
 
            // tạo H[i]
            vector<long long> H(m);
            for(int c = 0; c < m; c++)
                H[c] = a[x][c] + a[u][c];
 
            // prefix sum của H
            vector<long long> pref(m+1, 0);
            for(int c = 0; c < m; c++)
                pref[c+1] = pref[c] + H[c];
 
            long long bestLeft = LLONG_MIN;
 
            // quét cột v (phải)
            for(int v = 1; v < m; v++){
                // cập nhật best y
                long long yValue = colSum[v-1] + H[v-1] - pref[v-1];
                bestLeft = max(bestLeft, yValue);
 
                long long curr = bestLeft + colSum[v] + H[v] + pref[v];
                ans = max(ans, curr);
            }
        }
    }
 
    cout << ans;
}
 

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3 4
1 1 1 1
1 -5 -5 1
1 1 1 1