#include <bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef pair<int,int> pii;
vector<vector<int> > matris;
int n,m;
typedef pair<lli,pii> data;
const int MAXN=1e3+5, MAXM=1e3+5;
vector<pii> komsu(int a,int b){
vector<pii> don;
for (int i = -1; i < 2; i++)
{
for (int j = -1; j < 2; j++)
{
if(a+i>=0 && a+i< n && b+j<m && b+j>=0 && (i!=0||j!=0) && (i==0 || j==0)){
don.push_back({a+i,b+j});
}
}
}
return don;
}
/*
3 3
1 7 5
3 6 9
4 8 3
* */
void rotate90(vector<vector<int> >& cevir,vector<vector<int> >& yeni){
/*
1 4 7 8
2 5 9 *
3 6 - |
*
*
*
3 2 1
6 5 4
- 9 7
| * 8
0,0 -> 0,2
1,0 -> 0,1
2,0 -> 0,0
ters çevir, n-ikinci * */
for (int i = 0; i < (int)cevir.size(); i++)
{
for (int j = 0; j < (int)cevir[0].size(); j++)
{
yeni[j][cevir.size()-i-1]=cevir[i][j];
}
}
}
/*
min en sağ aşağıda olsun:
value+k.y+k.x
max-min-(-max.x+-max.y+min.x+min.y+1)
*
* */
int ans=-1e7;
void solve(vector<vector<int> >& par){
vector<vector<int> > dp(par.size(),vector<int>(par[0].size(),-1e6));
for (int i = 0; i < par.size(); i++)
{
for (int j = 0; j < par[0].size(); j++)
{
dp[i][j]=max(dp[i][j],par[i][j]+i+j);
if(i!=0)dp[i][j]=max(dp[i][j],dp[i-1][j]);
if(j!=0)dp[i][j]=max(dp[i][j],dp[i][j-1]);
}
}
for (int i = 0; i < par.size(); i++)
{
for (int j = 0; j < par[0].size(); j++)
{
ans=max(ans,dp[i][j]-par[i][j]-i-j-1);
//cout << ans<<"\n";
}
}
}
void yazdir(vector<vector<int> > matris){
for (int i = 0; i < (int) matris.size(); i++)
{
for (int j = 0; j<(int) matris[0].size() ; j++)
{
cout<<matris[i][j]<<" ";
}
cout <<"\n";
}
}
/*
4 5
8 7 6 9 16
3 12 19 33 21
9 9 9 9 9
15 14 13 11 17
1 4
2 4
* */
int main(){
cin>>n>>m;
matris=vector<vector<int> >(n,vector<int>(m,0));
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
scanf("%d",&matris[i][j]);
}
}
vector<vector<int> > eski,yeni,yeni2,yeni3;
for(int i=0;i<n;i++){
eski.push_back(vector<int>());
for(int j=0;j<m;j++){
eski[i].push_back(matris[i][j]);
}
}
solve(matris);
yeni=vector<vector<int> >(matris[0].size(),vector<int>(matris.size()));
rotate90(matris,yeni);
solve(yeni);
yeni2=vector<vector<int> >(yeni[0].size(),vector<int>(yeni.size()));
rotate90(yeni,yeni2);
solve(yeni2);
yeni3=vector<vector<int> >(yeni2[0].size(),vector<int>(yeni2.size()));
rotate90(yeni2,yeni3);
solve(yeni3);
/*for (int i = 0; i < 4; i++)
{
//cout <<"iter: "<<i<<"\n";
solve(eski);
//cout << "ans: "<<ans<<" ";
//cout <<"\n";
//yazdir(eski);
rotate90(eski,yeni);
//yazdir(yeni);
eski=yeni;
}*/
cout <<ans<<"\n";
return 0;
}
