Language: C++

#include <bits/stdc++.h>
using namwspace std;
int main(){
  char a,b;
  cin>>a>>b;
  if(a=='H'){
    if(b=='H'){
      cout<<'H'<<endl;
    }
    else if(b=='D'){
      cout<<'D'<<endl;
    }
  }
  else if(a=='D'){
    if(b=='H'){
      cout<<'D'<<endl;
    }
    else if(b=='D'){
      cout<<'H'<<endl;
    }
  }
  return 0;
}

Compiler output:
a.cc:2:7: error: expected nested-name-specifier before 'namwspace'
    2 | using namwspace 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>>a>>b;
      |   ^~~
      |   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:8:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |       cout<<'H'<<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:8:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |       cout<<'H'<<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<<'D'<<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:11:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |       cout<<'D'<<endl;
      |                  ^~~~
      |                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:16:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   16 |       cout<<'D'<<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:16:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   16 |       cout<<'D'<<endl;
      |                  ^~~~
      |                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:19:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   19 |       cout<<'H'<<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:19:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   19 |       cout<<'H'<<endl;
      |                  ^~~~
      |                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~