#include<iostream>
#include<vector>
#include<algorithm>
#include<utility>
#include<cmath>
using namespace std;
typedef long long ll;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<vector<ll>> vec(n + 1, vector<ll>(m + 1));
    for(int i = 1; i <= n; i++) for(int j = 1; j <= m; j++) cin >> vec[i][j];
    ll ans = 0;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            for(int k = 1; k <= n; k++){
                for(int l = 1; l <= m; l++){
                    ans = max(ans, llabs(vec[i][j] - vec[k][l]) - llabs(i - k) - llabs(j - l));
                }
            }
        }
    }
    cout << ans - 1 << "\n";
}
// g++ -std=c++17 -Wall -Wextra -Wshadow -fsanitize=undefined -fsanitize=address -o run pA.cpp -g
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