#include<iostream>
using namespace std;
const int N = 210;
long long a[N][N], sum[N][N], ans = -2e18;
int main(){
    freopen("ring.in","r",stdin);
    freopen("ring.out","w",stdout);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i ++){
        for(int j = 1; j <= m; j ++){
            cin >> a[i][j];
            a[n+i][j] = a[i][m+j] = a[n+i][m+j] = a[i][j];
            ans = max(ans, a[i][j]);
        }
    }   
    for (int i = 1; i <= 2*n; i++){
        for (int j = 1; j <= 2*m; j ++){
            sum[i][j] = sum[i-1][j] + a[i][j];
        }
    }
    if(ans <= 0){
        cout << ans << endl;
    }else{
        ans = -0x3f3f3f3f;
        for(int i = 1; i <= n; i ++){
            for (int j = i; j <= 2*n && j-i+1 <= n; j ++){
                for (int u = 1; u <= m; u ++){
                    long long sumt = 0;
                    for(int k = u; k <= 2*m && k - u + 1 <= m; k ++){
                        sumt += sum[j][k] - sum[i-1][k];

                        if(sumt < 0) sumt = 0;
                        ans = max(ans, sumt);
                    }
                }

            }
        }
        cout << ans << endl;
    }
    return 0;
}