Language: C++

#include <iostream>
using namespacw std;

int main(){
int a,b;
  cin>>a>>b;
  if(a%3==0){cout<<"possible"<<endl;}
  else if(b%3==0){cout<<"possible"<<endl;}
  else if((a+b)%3==0){cout<<"possible"<<endl;}
  else{cout<<"impossible"<<endl;}
}

Compiler output:
a.cc:2:7: error: expected nested-name-specifier before 'namespacw'
    2 | using namespacw std;
      |       ^~~~~~~~~
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |   cin>>a>>b;
      |   ^~~
      |   std::cin
In file included 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:7:14: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    7 |   if(a%3==0){cout<<"possible"<<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:7:32: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    7 |   if(a%3==0){cout<<"possible"<<endl;}
      |                                ^~~~
      |                                std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:8:19: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |   else if(b%3==0){cout<<"possible"<<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:8:37: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |   else if(b%3==0){cout<<"possible"<<endl;}
      |                                     ^~~~
      |                                     std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:9:23: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |   else if((a+b)%3==0){cout<<"possible"<<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:9:41: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    9 |   else if((a+b)%3==0){cout<<"possible"<<endl;}
      |                                         ^~~~
      |                                         std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:10:8: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |   else{cout<<"impossible"<<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:10:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 |   else{cout<<"impossible"<<endl;}
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~