#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=61,INF=1000000000; using namespace std; ll n,m,ans=-INF; vector<vector<ll>>nums(sz,vector<ll>(sz)); vector<vector<bool>>isSeen(sz,vector<bool>(sz)); void dfs(ll num1,ll num2,ll num3,ll num4,ll num5) { if(num1>=1 && num1<=n && num2>=1 && num2<=m && !isSeen[num1][num2]) { isSeen[num1][num2]=true; ans=max(ans,num4-num3-num5); dfs(num1+1,num2,min(num3,nums[num1+1][num2]),max(num4,nums[num1+1][num2]),num5+1); dfs(num1-1,num2,min(num3,nums[num1-1][num2]),max(num4,nums[num1-1][num2]),num5+1); dfs(num1,num2+1,min(num3,nums[num1][num2+1]),max(num4,nums[num1][num2+1]),num5+1); dfs(num1,num2-1,min(num3,nums[num1][num2-1]),max(num4,nums[num1][num2-1]),num5+1); } } void solve() { cin>>n>>m; for(int i=1;i<=n;i++) { for(int j=1;j<=m;j++) { cin>>nums[i][j]; } } for(int i=1;i<=n;i++) { for(int j=1;j<=m;j++) { for(int k=0;k<sz;k++) { for(int l=0;l<sz;l++) { isSeen[k][l]=false; } } dfs(i,j,nums[i][j],nums[i][j],1); } } cout<<ans; } int main() { fastIO; ll t=1; //cin>>t; while(t--) { solve(); } }