Main.cc: In function ‘int main()’:
Main.cc:6:2: error: ‘cin’ was not declared in this scope; did you mean ‘std::cin’?
    6 |  cin>>n>>m>>k;
      |  ^~~
      |  std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:75,
                 from Main.cc:1:
/usr/include/c++/9/iostream:60:18: note: ‘std::cin’ declared here
   60 |   extern istream cin;  /// Linked to standard input
      |                  ^~~
Main.cc:7:2: error: ‘vector’ was not declared in this scope; did you mean ‘std::vector’?
    7 |  vector<string> d(n);
      |  ^~~~~~
      |  std::vector
In file included from /usr/include/c++/9/vector:67,
                 from /usr/include/c++/9/queue:61,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:86,
                 from Main.cc:1:
/usr/include/c++/9/bits/stl_vector.h:386:11: note: ‘std::vector’ declared here
  386 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
Main.cc:7:9: error: ‘string’ was not declared in this scope; did you mean ‘std::string’?
    7 |  vector<string> d(n);
      |         ^~~~~~
      |         std::string
In file included from /usr/include/c++/9/iosfwd:39,
                 from /usr/include/c++/9/ios:38,
                 from /usr/include/c++/9/istream:38,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from Main.cc:1:
/usr/include/c++/9/bits/stringfwd.h:79:33: note: ‘std::string’ declared here
   79 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
Main.cc:7:17: error: ‘d’ was not declared in this scope
    7 |  vector<string> d(n);
      |                 ^
Main.cc:17:9: error: ‘max’ was not declared in this scope; did you mean ‘std::max’?
   17 |  int x1=max(x-k+1,0),y1=max(y-k+1,0);
      |         ^~~
      |         std::max
In file included from /usr/include/c++/9/algorithm:62,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:65,
                 from Main.cc:1:
/usr/include/c++/9/bits/stl_algo.h:3468:5: note: ‘std::max’ declared here
 3468 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
Main.cc:18:9: error: ‘min’ was not declared in this scope; did you mean ‘std::min’?
   18 |  int x2=min(x+k-1,m-1),y2=min(y+k-1,n-1);
      |         ^~~
      |         std::min
In file included from /usr/include/c++/9/algorithm:62,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:65,
                 from Main.cc:1:
/usr/include/c++/9/bits/stl_algo.h:3456:5: note: ‘std::min’ declared here
 3456 |     min(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
Main.cc:20:12: error: invalid conversion from ‘double (*)(double) throw ()’ {aka ‘double (*)(double)’} to ‘int’ [-fpermissive]
   20 |  for(int i=y1;i<=y2-k+1;++i)
      |            ^~
      |            |
      |            double (*)(double) throw () {aka double (*)(double)}
Main.cc:20:18: error: ‘y2’ was not declared in this scope; did you mean ‘x2’?
   20 |  for(int i=y1;i<=y2-k+1;++i)
      |                  ^~
      |                  x2
Main.cc:33:2: error: ‘cout’ was not declared in this scope; did you mean ‘std::cout’?
   33 |  cout<<ma;
      |  ^~~~
      |  std::cout
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:75,
                 from Main.cc:1:
/usr/include/c++/9/iostream:61:18: note: ‘std::cout’ declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~