func_code_string: #include <bits/stdc++.h>   const int N = 105;   int n, m;   char a[N][N];   struct Node {     int ax, ay, bx, by, cx, cy;   };   void work(int i, int j, int mask) {     for (int x = 0; x < 2; ++x) {       for (int y = 0; y < 2; ++y) {         if (mask >> (x << 1 | y) & 1) {           a[i][j] ^= 1, a[i][j + 1] ^= 1, a[i + 1][j] ^= 1, a[i + 1][j + 1] ^= 1;           a[i + x][j + y] ^= 1;         }       }     }   }   void solve() {     std::cin >> n >> m;     for (int i = 0; i < n; ++i) {       std::cin >> a[i];     }     std::vector<Node> ans;     if ((n & 1) && (m & 1) && a[n - 1][m - 1] ==  1 ) {       ans.push_back({n - 1, m - 1, n - 2, m - 1, n - 1, m - 2});       a[n - 1][m - 1] =  0 ;       a[n - 2][m - 1] ^= 1;       a[n - 1][m - 2] ^= 1;     }     if (m & 1) {       for (int i = 0; i < n - 1; i += 2) {         if (a[i][m - 1] ==  1  && a[i + 1][m - 1] ==  1 ) {           ans.push_back({i, m - 2, i, m - 1, i + 1, m - 1});           a[i][m - 2] ^= 1;         } else if (a[i][m - 1] ==  1 ) {           ans.push_back({i, m - 2, i + 1, m - 2, i + 1, m - 1});           ans.push_back({i, m - 2, i, m - 1, i + 1, m - 1});           a[i + 1][m - 2] ^= 1;         } else if (a[i + 1][m - 1] ==  1 ) {           ans.push_back({i, m - 2, i + 1, m - 2, i, m - 1});           ans.push_back({i, m - 2, i, m - 1, i + 1, m - 1});           a[i + 1][m - 2] ^= 1;         }       }       --m;     }     if (n & 1) {       for (int i = 0; i < m - 1; i += 2) {         if (a[n - 1][i] ==  1  && a[n - 1][i + 1] ==  1 ) {           ans.push_back({n - 2, i, n - 1, i, n - 1, i + 1});           a[n - 2][i] ^= 1;         } else if (a[n - 1][i] ==  1 ) {           ans.push_back({n - 2, i, n - 2, i + 1, n - 1, i + 1});           ans.push_back({n - 2, i, n - 1, i, n - 1, i + 1});           a[n - 2][i + 1] ^= 1;         } else if (a[n - 1][i + 1] ==  1 ) {           ans.push_back({n - 2, i, n - 2, i + 1, n - 1, i});           ans.push_back({n - 2, i, n - 1, i, n - 1, i + 1});           a[n - 2][i + 1] ^= 1;         }       }       --n;     }     for (int i = 0; i < n; i += 2) {       for (int j = 0; j < m; j += 2) {         for (int k = 0; k < 16; ++k) {           work(i, j, k);           if (a[i][j] ==  0  && a[i][j + 1] ==  0  && a[i + 1][j] ==  0  &&               a[i + 1][j + 1] ==  0 ) {             for (int x = 0; x < 2; ++x) {               for (int y = 0; y < 2; ++y) {                 if (k >> (x << 1 | y) & 1) {                   std::vector<int> p;                   for (int dx = 0; dx < 2; ++dx) {                     for (int dy = 0; dy < 2; ++dy) {                       if (x != dx || y != dy) {                         p.push_back(i + dx);                         p.push_back(j + dy);                       }                     }                   }                   ans.push_back({p[0], p[1], p[2], p[3], p[4], p[5]});                 }               }             }             break;           }           work(i, j, k);         }       }     }     std::cout << ans.size() <<   n ;     for (auto v : ans) {       std::cout << v.ax + 1 <<     << v.ay + 1 <<    ;       std::cout << v.bx + 1 <<     << v.by + 1 <<    ;       std::cout << v.cx + 1 <<     << v.cy + 1 <<   n ;     }   }   int main() {     std::ios_base::sync_with_stdio(false);     std::cin.tie(0);     int T = 1;     std::cin >> T;     while (T--) {       solve();     }   }   