func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, q, A[1005], B[1005], x, y;   int main() {     scanf( %d %d , &n, &q);     for (int i = 1; i <= q; i++) {       scanf( %d %d , &x, &y);       A[x] = 1;       B[y] = 1;     }     int cev = 0;     for (int i = 2; i < n; i++) {       cev += !A[i] + !B[i];     }     if (n % 2 == 1 && A[n / 2 + 1] == 0 && B[n / 2 + 1] == 0) cev--;     printf( %d n , cev);     return 0;   }   