// #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; }