#include <bits/stdc++.h>
using namespace std;
#define EmiliaMyWife ios::sync_with_stdio(0); cin.tie(0);
using ll = int64_t;
using ull = uint64_t;
using uint = uint32_t;
using ld = long double;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const ll LINF = ll(2e18) + ll(1e15);
const double EPS = 1e-8;
static auto LamyIsCute = []() {
EmiliaMyWife
return 48763;
}();
signed main() {
int n, m;
cin >> n >> m;
vector<vector<int>> arr(n, vector<int>(m));
for(int i = 0; i < n; i++)
for(int j = 0; j < m; j++)
cin >> arr[i][j];
int ans = -INF;
auto calc = [&]() {
vector<vector<int>> mx(n, vector<int>(m, -INF)), mx2(n, vector<int>(m, -INF));
for(int i = 0; i < n; i++) {
for(int j = 0; j < m; j++) {
mx[i][j] = -arr[i][j] + i + j;
mx2[i][j] = arr[i][j] + i + j;
if(i) {
mx[i][j] = max(mx[i][j], mx[i - 1][j]);
mx2[i][j] = max(mx2[i][j], mx2[i - 1][j]);
}
if(j) {
mx[i][j] = max(mx[i][j], mx[i][j - 1]);
mx2[i][j] = max(mx2[i][j], mx2[i][j - 1]);
}
ans = max(ans, arr[i][j] - i - j + mx[i][j] - 1);
ans = max(ans, mx2[i][j] - i - j - arr[i][j] - 1);
}
}
};
calc();
reverse(arr.begin(), arr.end());
calc();
cout << ans << '\n';
}
