answer.code:1:1: error: ‘include’ does not name a type
    1 | include <iostream>
      | ^~~~~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:62,
                 from /usr/include/c++/13/vector:62,
                 from answer.code:2:
/usr/include/c++/13/ext/type_traits.h:164:35: error: ‘constexpr const bool __gnu_cxx::__is_null_pointer’ redeclared as different kind of entity
  164 |   __is_null_pointer(std::nullptr_t)
      |                                   ^
/usr/include/c++/13/ext/type_traits.h:159:5: note: previous declaration ‘template<class _Type> constexpr bool __gnu_cxx::__is_null_pointer(_Type)’
  159 |     __is_null_pointer(_Type)
      |     ^~~~~~~~~~~~~~~~~
/usr/include/c++/13/ext/type_traits.h:164:26: error: ‘nullptr_t’ is not a member of ‘std’
  164 |   __is_null_pointer(std::nullptr_t)
      |                          ^~~~~~~~~
In file included from /usr/include/c++/13/bits/stl_pair.h:60,
                 from /usr/include/c++/13/bits/stl_algobase.h:64:
/usr/include/c++/13/type_traits:275:27: error: ‘size_t’ has not been declared
  275 |   template <typename _Tp, size_t = sizeof(_Tp)>
      |                           ^~~~~~
/usr/include/c++/13/type_traits:510:26: error: ‘std::size_t’ has not been declared
  510 |   template<typename _Tp, std::size_t _Size>
      |                          ^~~
/usr/include/c++/13/type_traits:511:25: error: ‘_Size’ was not declared in this scope
  511 |     struct is_array<_Tp[_Size]>
      |                         ^~~~~
/usr/include/c++/13/type_traits:511:31: error: template argument 1 is invalid
  511 |     struct is_array<_Tp[_Size]>
      |                               ^
/usr/include/c++/13/type_traits:617:33: error: ‘nullptr_t’ is not a member of ‘std’
  617 |     struct is_null_pointer<std::nullptr_t>
      |                                 ^~~~~~~~~
/usr/include/c++/13/type_traits:617:42: error: template argument 1 is invalid
  617 |     struct is_null_pointer<std::nullptr_t>
      |                                          ^
/usr/include/c++/13/type_traits:621:48: error: template argument 1 is invalid
  621 |     struct is_null_pointer<const std::nullptr_t>
      |                                                ^
/usr/include/c++/13/type_traits:625:51: error: template argument 1 is invalid
  625 |     struct is_null_pointer<volatile std::nullptr_t>
      |                                                   ^
/usr/include/c++/13/type_traits:629:57: error: template argument 1 is invalid
  629 |     struct is_null_pointer<const volatile std::nullptr_t>
      |                                                         ^
/usr/include/c++/13/type_traits:914:26: error: ‘size_t’ has not been declared
  914 |   template<typename _Tp, size_t _Size>
      |                          ^~~~~~
/usr/include/c++/13/type_traits:915:40: error: ‘_Size’ was not declared in this scope
  915 |     struct __is_array_known_bounds<_Tp[_Size]>
      |                                        ^~~~~
/usr/include/c++/13/type_traits:915:46: error: template argument 1 is invalid
  915 |     struct __is_array_known_bounds<_Tp[_Size]>
      |                                              ^
/usr/include/c++/13/type_traits:1348:37: error: ‘size_t’ is not a member of ‘std’
 1348 |     : public integral_constant<std::size_t, alignof(_Tp)>
      |                                     ^~~~~~
/usr/include/c++/13/type_traits:1348:57: error: template argument 1 is invalid
 1348 |     : public integral_constant<std::size_t, alignof(_Tp)>
      |                                                         ^
/usr/include/c++/13/type_traits:1348:57: note: invalid template non-type parameter
/usr/include/c++/13/type_traits:1357:37: error: ‘size_t’ is not a member of ‘std’
 1357 |     : public integral_constant<std::size_t, 0> { };
      |                                     ^~~~~~
/usr/include/c++/13/type_traits:1357:46: error: template argument 1 is invalid
 1357 |     : public integral_constant<std::size_t, 0> { };
      |                                              ^
/usr/include/c++/13/type_traits:1357:46: note: invalid template non-type parameter
/usr/include/c++/13/type_traits:1359:26: error: ‘std::size_t’ has not been declared
 1359 |   template<typename _Tp, std::size_t _Size>
      |                          ^~~
/usr/include/c++/13/type_traits:1360:21: error: ‘_Size’ was not declared in this scope
 1360 |     struct rank<_Tp[_Size]>
      |                     ^~~~~
/usr/include/c++/13/type_traits:1360:27: error: template argument 1 is invalid
 1360 |     struct rank<_Tp[_Size]>
      |                           ^
/usr/include/c++/13/type_traits:1361:37: error: ‘size_t’ is not a member of ‘std’
 1361 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
      |                                     ^~~~~~
/usr/include/c++/13/type_traits:1361:65: error: template argument 1 is invalid
 1361 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
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