func_code_string: #include <bits/stdc++.h>   using namespace std;   int b[1002][1002] = {0};   int main() {     int a[8][3] = {{7, 3, 5}, {2, 6, 4}, {1, 5, 7}, {0, 4, 6},                    {3, 7, 1}, {0, 2, 6}, {1, 3, 5}, {0, 2, 4}};     int x[8];     int y[8];     int d[8];     int n;     int m;     int tmpx, tmpy;     int sum = 0;     cin >> n >> m;     if (n == 2) {       cout <<  0 n ;       return 0;     }     for (int i = 0; i < m; ++i) {       cin >> tmpx >> tmpy;       b[tmpx][1] = 1;       b[tmpx][n] = 1;       b[1][tmpy] = 1;       b[n][tmpy] = 1;     }     for (int i = 2; i <= n / 2; ++i) {       x[0] = i;       x[1] = n + 1 - i;       x[2] = n;       x[3] = n;       x[4] = n + 1 - i;       x[5] = i;       x[6] = 1;       x[7] = 1;       y[0] = 1;       y[1] = 1;       y[2] = i;       y[3] = n + 1 - i;       y[4] = n;       y[5] = n;       y[6] = n + 1 - i;       y[7] = i;       bool g = false;       int count;       int mx = 0;       for (int j = 0; j < 256; ++j) {         count = 0;         for (int k = 0; k < 8; ++k) {           d[k] = ((j >> k) & 1);           count += d[k];         }         g = false;         for (int k = 0; k < 8 && (!g); ++k) {           if (d[k] == 1) {             if (b[x[k]][y[k]] == 1) {               g = true;               break;             }             for (int u = 0; u < 3; ++u) {               if (d[a[k][u]] == 1) {                 g = true;                 break;               }             }           }         }         if (g) continue;         if (count > mx) mx = count;       }       sum += mx;     }     if (n % 2 == 1) {       if (b[n / 2 + 1][1] == 0 || b[n / 2 + 1][n] == 0 || b[1][n / 2 + 1] == 0 ||           b[n][n / 2 + 1] == 0) {         ++sum;       }     }     cout << sum <<   n ;     return 0;   }   