// 01001100 01001111 01010100 01000001 \\ // \\ // ╦ ╔═╗╔╦╗╔═╗ \\ // ║ ║ ║ ║ ╠═╣ \\ // ╩═╝╚═╝ ╩ ╩ ╩ \\ // \\ // 01001100 01001111 01010100 01000001 \\ #include <bits/stdc++.h> using namespace std; #define nl '\n' #define ff first #define ss second #define ll long long #define ld long double #define terminator main #define pll pair<ll,ll> #define add insert #define append push_back #define pii pair<int,int> #define all(x) (x).begin(),(x).end() #define L0TA ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL) const int N = 1e3 + 3; int a[N][N]; int x[N][N][4]; void solve(){ int n, m, ans; cin >> n >> m; for(int i = 1; i <= n; i++) for(int j = 1; j <= m; j++) cin >> a[i][j]; for(int i = 0; i < n + 2; i++) for(int j = 0; j < m + 2; j++) for(int k = 0; k < 4; k++) x[i][j][k] = -1e9; ans = -1e9; for(int i = 1; i <= n; i++){ for(int j = 1; j <= m; j++){ x[i][j][0] = max(x[i - 1][j][0], x[i][j - 1][0]); ans = max(ans, a[i][j] - i - j + x[i][j][0] - 1); x[i][j][0] = max(x[i][j][0], - a[i][j] + i + j); } } for(int i = 1; i <= n; i++){ for(int j = m; j > 0; j--){ x[i][j][1] = max(x[i - 1][j][1], x[i][j + 1][1]); ans = max(ans, a[i][j] - i + j + x[i][j][1] - 1); x[i][j][1] = max(x[i][j][1], - a[i][j] + i - j); } } for(int i = n; i > 0; i--){ for(int j = 1; j <= m; j++){ x[i][j][2] = max(x[i + 1][j][2], x[i][j - 1][2]); ans = max(ans, a[i][j] + i - j + x[i][j][2] - 1); x[i][j][2] = max(x[i][j][2], - a[i][j] - i + j); } } for(int i = n; i > 0; i--){ for(int j = m; j > 0; j--){ x[i][j][3] = max(x[i + 1][j][3], x[i][j + 1][3]); ans = max(ans, a[i][j] + i + j + x[i][j][3] - 1); x[i][j][3] = max(x[i][j][3], - a[i][j] - i - j); } } cout << ans; } int terminator(){ L0TA; int T = 1; //cin >> T; while(T--) solve(); return 0; }