func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAX = 2005;   bool a[MAX][MAX], row[MAX], col[MAX];   int main() {     ios::sync_with_stdio(false);     int n;     cin >> n;     for (int i = 0; i < n; i++)       for (int j = 0; j < n; j++) {         char c;         cin >> c;         a[i][j] = (c ==  1 );       }     int ans = 0;     for (int i = 0; i < n; i++)       for (int j = n - 1; j > i; j--)         if (a[i][j] ^ row[i] ^ col[j]) {           a[i][j] = false;           row[i] = !row[i];           col[j] = !col[j];           ans++;         }     for (int i = 0; i < n; i++) {       a[i][i] ^= row[i] ^ col[i];       row[i] = col[i] = false;     }     for (int j = 0; j < n; j++)       for (int i = n - 1; i > j; i--)         if (a[i][j] ^ row[i] ^ col[j]) {           a[i][j] = false;           row[i] = !row[i];           col[j] = !col[j];           ans++;         }     for (int i = 0; i < n; i++) ans += (a[i][i] ^ row[i] ^ col[i]);     cout << ans;     return 0;   }   