Language: C++

#include <bits/stdc++.h>
using namepsace std;
int main(){
  int n,m;
  cin >> n >> m;
  if(n==2||m==2){
    cout << 0 << endl;
  }
  else if(n==1||m==1){
    if(n==1&&m==1){
      cout << 0 << endl;
    }
    else{
      cout << max(n,m)-2 <<endl;
    }
  }
  else{
    cout << (n-2)*(m-2) << endl;
  }
}

Compiler output:
a.cc:2:7: error: expected nested-name-specifier before 'namepsace'
    2 | using namepsace std;
      |       ^~~~~~~~~
a.cc: In function 'int main()':
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin >> n >> m;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:7:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    7 |     cout << 0 << endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:7:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    7 |     cout << 0 << endl;
      |                  ^~~~
      |                  std::endl
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:11:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |       cout << 0 << endl;
      |       ^~~~
      |       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:11:20: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |       cout << 0 << endl;
      |                    ^~~~
      |                    std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:14:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   14 |       cout << max(n,m)-2 <<endl;
      |       ^~~~
      |       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:14:15: error: 'max' was not declared in this scope; did you mean 'std::max'?
   14 |       cout << max(n,m)-2 <<endl;
      |               ^~~
      |               std::max
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: 'std::max' declared here
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
a.cc:14:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   14 |       cout << max(n,m)-2 <<endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:18:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   18 |     cout << (n-2)*(m-2) << endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:18:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   18 |     cout << (n-2)*(m-2) << endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~