func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     int n, m;     cin >> n >> m;     vector<long int> a[n + 1], b[n + 1];     vector<pair<int, int> > v;     for (int i = 0; i <= n; i++) a[i].resize(m + 1), b[i].resize(m + 1);     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) cin >> a[i][j];     }     for (int i = 1; i <= n - 1; i++) {       for (int j = 1; j <= m - 1; j++) {         if (a[i][j + 1] == 1 && a[i + 1][j] == 1 && a[i + 1][j + 1] == 1 &&             a[i][j] == 1) {           v.push_back(make_pair(i, j));           b[i][j + 1] = 1;           b[i][j] = 1;           b[i + 1][j] = 1;           b[i + 1][j + 1] = 1;         }       }     }     int ct = 1;     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         if (a[i][j] != b[i][j]) ct = 0;       }     }     if (ct == 0)       cout << -1;     else {       cout << v.size() <<   n ;       for (int i = 0; i < v.size(); i++)         cout << v[i].first <<     << v[i].second <<   n ;     }   }   