#include <bits/stdc++.h>
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define fast ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
#define all(v) v.begin(),v.end()
#define pb push_back
#define sz size()
#define ft first
#define sd second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef unsigned long long ull;
const int N = 1e6 + 5;
const ll M = 1e8;
const ll inf = 1e18;
const ll mod = 1e9;
const double Pi = acos(-1);
ll binpow(ll x, ll ti) { ll res = 1;while (ti){if(ti & 1)res *= x;x *= x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll binmul(ll x, ll ti) { ll res = 0;while (ti){if(ti & 1)res += x;x += x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll nok(ll a, ll b) { return (a*b)/__gcd(abs(a),abs(b)) * (a*b > 0 ? 1 : -1); }
bool odd(ll n) { return (n % 2 == 1); }
bool even(ll n) { return (n % 2 == 0); }
ll n, m, a[1005][1005], pr1[1005][1005], pr2[1005][1005], sf1[1005][1005], sf2[1005][1005];
const void solve(/*Armashka*/) {
cin >> n >> m;
for (int i = 1; i <= n; ++ i) {
for (int j = 1; j <= m; ++ j) {
cin >> a[i][j];
}
}
for (int i = 1; i <= n; ++ i) pr1[i][0] = pr2[i][0] = sf1[i][0] = sf2[i][0] = pr1[i][m + 1] = pr2[i][m + 1] = sf1[i][m + 1] = sf2[i][m + 1] = -inf;
for (int i = 1; i <= m; ++ i) pr1[0][i] = pr2[0][i] = sf1[0][i] = sf2[0][i] = pr1[n + 1][i] = pr2[n + 1][i] = sf1[n + 1][i] = sf2[n + 1][i] = -inf;
for (int i = 1; i <= n; ++ i) {
for (int j = 1; j <= m; ++ j) {
pr1[i][j] = max({pr1[i - 1][j], pr1[i][j - 1], -a[i][j] + i + j});
}
}
for (int i = n; i >= 1; -- i) {
for (int j = 1; j <= m; ++ j) {
pr2[i][j] = max({pr2[i + 1][j], pr2[i][j - 1], -a[i][j] - i + j});
}
}
for (int i = 1; i <= n; ++ i) {
for (int j = m; j >= 1; -- j) {
sf1[i][j] = max({sf1[i - 1][j], sf1[i][j + 1], -a[i][j] + i - j});
}
}
for (int i = n; i >= 1; -- i) {
for (int j = m; j >= 1; -- j) {
sf2[i][j] = max({sf2[i + 1][j], sf2[i][j + 1], -a[i][j] - i - j});
}
}
ll ans = -inf;
for (int i = 1; i <= n; ++ i) {
for (int j = 1; j <= m; ++ j) {
ll res = pr1[i][j] + a[i][j] - i - j;
res = max(res, pr2[i][j] + a[i][j] + i - j);
res = max(res, sf1[i][j] + a[i][j] - i + j);
res = max(res, sf2[i][j] + a[i][j] + i + j);
//cout << res << " ";
ans = max(ans, res);
} //cout << "\n";
}
cout << ans - 1 << "\n";
}
signed main() {
fast;
//freopen("divide.in", "r", stdin);
//freopen("divide.out", "w", stdout);
int tt = 1;
//cin >> tt;
while (tt --) {
solve();
}
}
/*
5 4 4
1 2
3 1
3 4
5 3
4 5 2 3
2 1 3 1
1 3 5
2 3 4 5
2 1 3 1
*/
