// 01001100 01001111 01010100 01000001 \\
// \\
// ╦ ╔═╗╔╦╗╔═╗ \\
// ║ ║ ║ ║ ╠═╣ \\
// ╩═╝╚═╝ ╩ ╩ ╩ \\
// \\
// 01001100 01001111 01010100 01000001 \\
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define ff first
#define ss second
#define ll long long
#define ld long double
#define terminator main
#define pll pair<ll,ll>
#define add insert
#define append push_back
#define pii pair<int,int>
#define all(x) (x).begin(),(x).end()
#define L0TA ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
const int N = 1e3 + 3;
int a[N][N];
void solve(){
int n, m, ans;
cin >> n >> m;
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++)
cin >> a[i][j];
ans = -1e9;
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++)
for(int p = 1; p <= n; p++)
for(int q = 1; q <= m; q++)
ans = max(ans, abs(a[i][j] - a[p][q]) - abs(i - p) - abs(j - q) - 1);
cout << ans;
}
int terminator(){
L0TA;
int T = 1;
//cin >> T;
while(T--)
solve();
return 0;
}
