#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
//#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 5000000000000000000
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
mt19937 rng(time(0));
ll randll(ll l, ll r){
return uniform_int_distribution<ll>(l, r)(rng);
}
int main() {
speed;
srand(time(0));
ll n, m;
cin >> n >> m;
vvll a(n, vll(m));
for (int i =0 ; i < n; i ++) {
for (int j = 0; j < m; j ++) {
cin >> a[i][j];
}
}
ll maxl = -INF;
for (int i = 0; i < n; i ++) {
for (int j = 0; j < m; j ++) {
for(int i1 = 0; i1 < n; i1 ++) {
for (int j1 = 0; j1 < m; j1 ++) {
maxl = max(maxl, abs(a[i][j]-a[i1][j1]) - (abs(i-i1) + abs(j-j1)+1));
}
}
}
}
cout << maxl << endl;
}
