Language: C++

#include<iostream>
using nam,namespace std;
int main()
{
  int a,b,c;
  cin>>a;
  cin>>b;
  if(a>b)
    swap(a,b);
  if(a==1 && b==2)
    cout<<"3"<<endl;
  else if(a==2 && b==3)
    cout<<"1"<<endl;
  else
    cout<<"2"<<endl;
}

Compiler output:
a.cc:2:7: error: expected nested-name-specifier before 'nam'
    2 | using nam,namespace 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;
      |   ^~~
      |   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:9:5: error: 'swap' was not declared in this scope
    9 |     swap(a,b);
      |     ^~~~
a.cc:9:5: note: suggested alternatives:
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/tuple:2823:5: note:   'std::swap'
 2823 |     swap(tuple<_Elements...>&, tuple<_Elements...>&) = delete;
      |     ^~~~
In file included from /usr/include/c++/14/bits/exception_ptr.h:41,
                 from /usr/include/c++/14/exception:166,
                 from /usr/include/c++/14/ios:41:
/usr/include/c++/14/bits/move.h:226:5: note:   'std::swap'
  226 |     swap(_Tp& __a, _Tp& __b)
      |     ^~~~
/usr/include/c++/14/bits/move.h:226:5: note:   'std::swap'
/usr/include/c++/14/bits/exception_ptr.h:229:5: note:   'std::__exception_ptr::swap'
  229 |     swap(exception_ptr& __lhs, exception_ptr& __rhs)
      |     ^~~~
a.cc:11:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |     cout<<"3"<<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:11:16: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |     cout<<"3"<<endl;
      |                ^~~~
      |                std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:13:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   13 |     cout<<"1"<<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:13:16: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   13 |     cout<<"1"<<endl;
      |                ^~~~
      |                std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:15:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   15 |     cout<<"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:15:16: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   15 |     cout<<"2"<<endl;
      |                ^~~~
      |                std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~