#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define X first
#define Y second
#define pii pair<int,int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
for (; l != r; ++l)
cout << *l << " \n"[l + 1 == r];
}
#ifdef Doludu
#define test(x...) abc("[" + string(#x) + "]", x);
#else
#define test(x...) void(0);
#endif
const int N = 1001;
int a[N][N], ul[N][N], ur[N][N], dl[N][N], dr[N][N];
int main () {
ios::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
for (int i = 0; i < n; ++i) for (int j = 0; j < m; ++j) {
cin >> a[i][j];
ul[i][j] = -a[i][j] + i + j;
ur[i][j] = -a[i][j] + i - j;
dl[i][j] = -a[i][j] - i + j;
dr[i][j] = -a[i][j] - i - j;
}
for (int i = 0; i < n; ++i) for (int j = 0; j < m; ++j) {
if (i)
ul[i][j] = max(ul[i][j], ul[i - 1][j]);
if (j)
ul[i][j] = max(ul[i][j], ul[i][j - 1]);
}
for (int i = 0; i < n; ++i) for (int j = m - 1; ~j; --j) {
if (i)
ur[i][j] = max(ur[i][j], ur[i - 1][j]);
if (j + 1 < m)
ur[i][j] = max(ur[i][j], ur[i][j + 1]);
}
for (int i = n - 1; ~i; --i) for (int j = 0; j < m; ++j) {
if (i + 1 < n)
dl[i][j] = max(dl[i][j], dl[i + 1][j]);
if (j)
dl[i][j] = max(dl[i][j], dl[i][j - 1]);
}
for (int i = n - 1; ~i; --i) for (int j = m - 1; ~j; --j) {
if (i + 1 < n)
dr[i][j] = max(dr[i][j], dr[i + 1][j]);
if (j + 1 < m)
dr[i][j] = max(dr[i][j], dr[i][j + 1]);
}
int ans = -1;
for (int i = 0; i < n; ++i) for (int j = 0; j < m; ++j) {
ans = max(ans, a[i][j] - i - j + ul[i][j] - 1);
ans = max(ans, a[i][j] - i + j + ur[i][j] - 1);
ans = max(ans, a[i][j] + i - j + dl[i][j] - 1);
ans = max(ans, a[i][j] + i + j + dr[i][j] - 1);
}
cout << ans << endl;
}
