#include <bits/stdc++.h> using namespace std; #define print(l) for(auto i:l) cout<<i<<" ";cout<<endl; #define input(t,l,n) vector<t>l(n);for(int i = 0;i<n;i++)cin>>l[i]; #define int long long #define pb push_back #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> #define all(l) l.begin(),l.end() #define pii pair<int,int> #define fi first #define se second const int M = 1e9+7; const int inf = 1e18; int bp(int x, int y, int p){ int res = 1; x = x % p; while (y > 0) { if (y & 1) res = (res * x) % p; y = y >> 1; x = (x * x) % p; } return res; } int MI(int n, int p){ return bp(n, p - 2, p); } int mul(int x,int y, int p){ return x * 1ull * y % p; } int di(int x,int y, int p){ return mul(x, MI(y, p), p); } int n , m , k , q; void solve(int testcase_number){ cin>>n>>m; // vector<vector<vector<int>>>dp(n+1,vecor<int>(m+1,vector<int>(3,0))); int dp[n+1][m+1][3] = {}; for(int i =0;i<=n;i++){ dp[i][0][0] = 0; dp[i][0][1] = inf; dp[i][0][2] = -inf; } for(int i =0;i<=m;i++){ dp[0][i][0] = 0; dp[0][i][1] = inf; dp[0][i][2] = -inf; } int mat[n+1][m+1]; for(int i = 1;i<=n;i++){ for(int j = 1;j<=m;j++){ cin>>mat[i][j]; } } int ans = 0; for(int i = 1;i<=n;i++){ for(int j = 1;j<=m;j++){ vector<int>p1(3,0); p1[0] = dp[i-1][j][0]; p1[1] = dp[i-1][j][1]; p1[2] = dp[i-1][j][2]; vector<int>p2(3,0); p2[0] = dp[i][j-1][0]; p2[1] = dp[i][j-1][1]; p2[2] = dp[i][j-1][2]; p2[1] = min(p2[1],mat[i][j]); p2[2] = max(p2[2],mat[i][j]); p1[1] = min(p1[1],mat[i][j]); p1[2] = max(p1[2],mat[i][j]); // cout<<min(p1[]mat[i][j]<<endl; // print(p1); // print(p2); if(p2[2]-p2[1]-p2[0]-1 > p1[2]-p1[1]-p1[0]-1){ dp[i][j][0] = p2[0]+1; dp[i][j][1] = p2[1]; dp[i][j][2] = p2[2]; } else if(p2[2]-p2[1]-p2[0]-1 < p1[2]-p1[1]-p1[0]-1){ dp[i][j][0] = p1[0]+1; dp[i][j][1] = p1[1]; dp[i][j][2] = p1[2]; } else{ if(p2[0] <= p1[0]){ dp[i][j][0] = p2[0]+1; dp[i][j][1] = p2[1]; dp[i][j][2] = p2[2]; } else{ dp[i][j][0] = p1[0]+1; dp[i][j][1] = p1[1]; dp[i][j][2] = p1[2]; } } ans = max(ans,dp[i][j][2]-dp[i][j][1]-dp[i][j][0]); } } cout<<ans<<endl; } signed main(){ ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE cin.tie(0), cout.tie(0); cout << fixed<<setprecision(9); int t = 1; // cin>>t; for(int i = 1;i<=t;i++){ solve(i); } }