#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define str string
#define pb push_back
#define pf push_front
#define in insert
#define all(v) v.begin(),v.end()
#define fastIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
const int sz=1000000,INF=1000000000;
using namespace std;
void solve()
{
ll n,m,ans=-INF;
cin>>n>>m;
vector<vector<ll>>nums(n+1,vector<ll>(m+1));
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
cin>>nums[i][j];
}
}
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
for(int k=0;k<n;k++)
{
for(int l=0;l<m;l++)
{
if(i!=k || j!=l)
{
ans=max(ans,abs(nums[i][j]-nums[k][l])-(abs(i-k)+abs(j-l)+1));
}
}
}
}
}
cout<<ans;
}
int main()
{
fastIO;
ll t=1;
//cin>>t;
while(t--)
{
solve();
}
}
