func_code_string: #include <bits/stdc++.h>   using namespace std;   using ll = long long;   const ll MOD = 1e9 + 7;   const int N = 2000;   int board[N][N];   bool flip_row[N];   bool flip_col[N];   int bar[N];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     int n;     cin >> n;     for (int y = 0; y < n; ++y) {       string str;       cin >> str;       for (int x = 0; x < n; ++x) {         if (str[x] ==  1 ) board[y][x] ^= 1;       }     }     for (int y = 0; y < n; ++y) {       string str;       cin >> str;       for (int x = 0; x < n; ++x) {         if (str[x] ==  1 ) board[y][x] ^= 1;       }     }     string str;     cin >> str;     for (int i = 0; i < n; ++i) {       if (str[i] ==  1 ) bar[i] ^= 1;     }     for (int y = 0; y < n; ++y) {       for (int x = 0; x < n; ++x) {         if (board[y][x]) {           if (!bar[y])             flip_row[y] = true;           else if (!bar[x])             flip_col[x] = true;         }       }     }     int y0 = 0;     for (y0 = 0; y0 < n; ++y0) {       if (!bar[y0]) continue;       for (int x = 0; x < n; ++x) {         if (bar[x] && board[y0][x]) {           flip_col[x] = true;         }       }       break;     }     for (int y = y0 + 1; y < n; ++y) {       if (!bar[y]) continue;       for (int x = 0; x < n; ++x) {         if (bar[x] && (board[y][x] ^ flip_col[x])) flip_row[y] = true;       }     }     bool fail = false;     for (int y = 0; y < n; ++y) {       for (int x = 0; x < n; ++x) {         if (flip_row[y]) board[y][x] ^= bar[x];         if (flip_col[x]) board[y][x] ^= bar[y];         if (board[y][x] == 1) fail = true;       }     }     if (fail) {       cout <<  -1 n ;     } else {       int cou = 0;       for (int i = 0; i < n; ++i) cou += flip_row[i] + flip_col[i];       cout << cou <<   n ;       for (int x = 0; x < n; ++x) {         if (flip_col[x]) cout <<  col   << x <<   n ;       }       for (int y = 0; y < n; ++y) {         if (flip_row[y]) cout <<  row   << y <<   n ;       }     }   }   