#include "bits/stdc++.h"
using namespace std;
#define int long long
#define ff first
#define ss second
int sol(vector <vector <int>> a) {
int n = a.size() - 1;
int m = a[0].size() - 1;
int ans = -1;
vector <vector <int>> dp1(n + 1, vector <int> (m + 1));
vector <vector <int>> dp2(n + 1, vector <int> (m + 1));
dp1[1][1] = a[1][1] + 1 + 1;
dp2[1][1] = a[1][1] - 1 - 1;
for (int i = 1; i <= n; i ++) {
for (int j = 1; j <= m; j ++) {
dp1[i][j] = a[i][j] + i + j;
dp2[i][j] = a[i][j] - i - j;
if (j != 1) dp1[i][j] = max(dp1[i][j], dp1[i][j - 1]);
if (i != 1) dp1[i][j] = max(dp1[i][j], dp1[i - 1][j]);
if (j != 1) dp2[i][j] = min(dp2[i][j], dp2[i][j - 1]);
if (i != 1) dp2[i][j] = min(dp2[i][j], dp2[i - 1][j]);
// cout << i << ' ' << j << ' ' << dp1[i][j] << ' ' << dp2[i][j] << endl;
// cout << dp1[i][j] - a[i][j] - i - j - 1 << endl;
// cout << a[i][j] - i - j - dp2[i][j] - 1 << endl;
ans = max({ans, dp1[i][j] - a[i][j] - i - j - 1, a[i][j] - i - j - dp2[i][j] - 1});
}
}
/* for (int i = 1; i <= n; i ++) {
for (int j = 1; j <= m; j ++) {
for (int x = 1; x <= i; x ++) {
for (int y = 1; y <= j; y ++) {
int s = abs(a[i][j] - a[x][y]) - (i - x) - (j - y) - 1;
s = abs(a[i][j] - a[x][y]) - i + x - j + y - 1;
if (a[i][j] < a[x][y]) {
s = a[x][y] + x + y - a[i][j] - i - j - 1;
s = a[x][y] + x + y - (a[i][j] + i + j) - 1;
} else {
s = a[i][j] - i - j - a[x][y] + x + y - 1;
s = a[i][j] - i - j - (a[x][y] - x - y) - 1;
}
ans = max(ans, abs(a[i][j] - a[x][y]) - abs(i - x) - abs(j - y) - 1);
}
}
}
} */
return ans;
}
signed main() {
int n, m;
cin >> n >> m;
vector <vector <int>> a(n + 1, vector <int> (m + 1));
for (int i = 1; i <= n; i ++) {
for (int j = 1; j <= m; j ++) cin >> a[i][j];
}
int ans = sol(a);
for (int i = 1; i <= n; i ++) {
reverse(a[i].begin() + 1, a[i].end());
}
ans = max(ans, sol(a));
cout << ans << endl;
return 0;
}
