// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
#include <numeric>
#include <stack>
#include <chrono>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
void fast_io() {
// freopen("", "r", stdin);
// freopen("", "w", stdout);
ios::sync_with_stdio(0);
cin.tie();
cout.tie();
cout << setprecision(9);
}
#define int long long
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define fi first
#define se second
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
void solve() {
int n, m; cin >> n >> m;
int a[n + 1][m + 1];
int ans = -1e18;
for (int i = 1; i <= n; i++){
for (int j = 1; j <= m; j++){
cin >> a[i][j];
}
}
int tl[n + 3][m + 3] = {}, dl[n + 3][m + 3], tr[n + 3][m + 3], dr[n + 3][m + 3];
for (int i = 0; i <= m + 1; i++){
tl[0][i] = tl[n + 1][i] = -1e18;
tr[0][i] = tr[n + 1][i] = -1e18;
dl[0][i] = dl[n + 1][i] = -1e18;
dr[0][i] = dr[n + 1][i] = -1e18;
}
for (int i = 0; i <= n + 1; i++){
tl[i][0] = tl[i][m + 1] = -1e18;
tr[i][0] = tr[i][m + 1] = -1e18;
dl[i][0] = dl[i][m + 1] = -1e18;
dr[i][0] = dr[i][m + 1] = -1e18;
}
for (int i = 1; i <= n; i++){
for (int j = 1; j <= m; j++){
tl[i][j] = max(tl[i - 1][j], tl[i][j - 1]);
tl[i][j] = max(tl[i][j], -a[i][j] + i + j);
}
}
for (int i = n; i >= 1; i--){
for (int j = 1; j <= m; j++){
dl[i][j] = max(dl[i + 1][j], dl[i][j - 1]);
dl[i][j] = max(dl[i][j], -a[i][j] - i + j);
}
}
for (int i = 1; i <= n; i++){
for (int j = m; j >= 1; j--){
tr[i][j] = max(tr[i - 1][j], tr[i][j + 1]);
tr[i][j] = max(tr[i][j], -a[i][j] + i - j);
}
}
for (int i = n; i >= 1; i--){
for (int j = m; j >= 1; j--){
dr[i][j] = max(dr[i + 1][j], dr[i][j + 1]);
dr[i][j] = max(dr[i][j], -a[i][j] - i - j);
}
}
for (int i = 1; i <= n; i++){
for (int j = 1; j <= m; j++){
int x = a[i][j];
int cur = -1e18;
cur = max(cur, tl[i][j] + x - i - j);
cur = max(cur, tr[i][j] + x - i + j);
// cout << cur - 1 << ' ';
cur = max(cur, dl[i][j] + x + i - j);
cur = max(cur, dr[i][j] + x - i + j);
ans = max(ans, cur - 1);
}
// cout << endl;
}
// cout << tr[1][2] /<< endl;
cout << ans << endl;
}
signed main() {
fast_io();
srand(chrono::steady_clock::now().time_since_epoch().count());
int tc = 1;
// cin >> tc;
while (tc--) solve();
return 0;
}
