// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <cmath>
#include <complex>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <tuple>
#include <vector>
using namespace std;
using lg = long long;
using pii = pair<int, int>;
using pll = pair<lg, lg>;
#define TEST cerr << "TEST" << endl
#define AMARI 998244353
// #define AMARI 1000000007
#define TEMOTO ((sizeof(long double) == 16) ? false : true)
#define TIME_LIMIT 1980 * (TEMOTO ? 1 : 1000)
#define el '\n'
#define El '\n'

#define MULTI_TEST_CASE false
void solve(void) {
    int h,w;
    cin >> h >> w;
    vector<vector<int>> a(h,vector<int>(w));
    vector<int> hsum(h,0),wsum(w,0);
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            cin >> a[i][j];
            hsum[i] += a[i][j];
            wsum[j] += a[i][j];
        }
    }
    
    int ans = 0;
    for(int i = 0; i < h; i++){
        for(int j = i + 1; j < h; j++){
            ans = max(ans,hsum[i] + hsum[j]);
        }
    }
    for(int i = 0; i < w; i++){
        for(int j = i + 1; j < w; j++){
            ans = max(ans,wsum[i] + wsum[j]);
        }
    }
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            ans = max(ans,hsum[i] + wsum[j] - a[i][j]);
        }
    }
    //i+jが一定(k)
    for(int k = 0; k < h + w; k++){
        int temp = 0;
        for(int i = 0; i < h + w; i++){
            if(i < h && k - i >= 0 && k - i < w)temp += a[i][k - i];
        }
        for(int i = 0; i < h; i++){
            int t2 = temp + hsum[i];
            int j = k - i;
            if(j >= 0 && j < w)t2 -= a[i][j];
            ans = max(ans,t2);
        }
        for(int j = 0; j < w; j++){
            int t2 = temp + wsum[j];
            int i = k - j;
            if(i >= 0 && i < h)t2 -= a[i][j];
            ans = max(ans,t2);
        }
    }

    //i-jが一定(k)
    for(int k = -1 * w; k < h; k++){
        int temp = 0;
        for(int i = 0; i < h + w; i++){
            if(i < h && i - k >= 0 && i - k < w)temp += a[i][i - k];
        }
        for(int i = 0; i < h; i++){
            int t2 = temp + hsum[i];
            int j = i - k;
            if(j >= 0 && j < w)t2 -= a[i][j];
            ans = max(ans,t2);
        }
        for(int j = 0; j < w; j++){
            int t2 = temp + wsum[j];
            int i = k + j;
            if(i >= 0 && i < h)t2 -= a[i][j];
            ans = max(ans,t2);
        }
    }
    cout << ans << el;
    return;
}

void calc(void) {
    return;
}

signed main(void) {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    calc();
    int t = 1;
    if(MULTI_TEST_CASE) cin >> t;
    while(t--) {
        solve();
    }
    return 0;
}