func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 1000000007;   const long long LLINF = 1000000000000000007LL;   const double EPS = 1e-9;   const int sz = 200100;   int ar[600][600];   int p[600][600];   int suf_sum_2d(int i1, int j1, int i2, int j2) {     return p[i2 + 1][j2 + 1] - p[i2 + 1][j1] - p[i1][j2 + 1] + p[i1][j1];   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int n, m;     cin >> n >> m;     for (int i = 0; i < n; ++i) {       for (int j = 0; j < m; ++j) {         cin >> ar[i][j];         p[i + 1][j + 1] = p[i][j + 1] + p[i + 1][j] - p[i][j] + ar[i][j];       }     }     int mx = -INF;     for (int i = 0; i < n; ++i) {       for (int j = 0; j < m; ++j) {         int r = min(min(i + 1, j + 1), min(n - i, m - j));         int res = ar[i][j];         for (int k = 1; k < r; ++k) {           res =               suf_sum_2d(i - k, j - k, i + k, j + k) - res - ar[i - k + 1][j - k];           mx = max(mx, res);         }       }     }     cout << mx;   }   