In file included from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:84,
                 from answer.code:4:
/usr/include/c++/11/numeric: In instantiation of ‘constexpr std::common_type_t<_Mn, _Nn> std::gcd(_Mn, _Nn) [with _Mn = double; _Nn = int; std::common_type_t<_Mn, _Nn> = double]’:
answer.code:28:25:   required from here
/usr/include/c++/11/numeric:169:21: error: static assertion failed: std::gcd arguments must be integers
  169 |       static_assert(is_integral_v<_Mn>, "std::gcd arguments must be integers");
      |                     ^~~~~~~~~~~~~~~~~~
/usr/include/c++/11/numeric:169:21: note: ‘std::is_integral_v<double>’ evaluates to false
In file included from /usr/include/c++/11/bits/move.h:57,
                 from /usr/include/c++/11/bits/nested_exception.h:40,
                 from /usr/include/c++/11/exception:148,
                 from /usr/include/c++/11/ios:39,
                 from /usr/include/c++/11/ostream:38,
                 from /usr/include/c++/11/iostream:39,
                 from answer.code:1:
/usr/include/c++/11/type_traits: In instantiation of ‘struct std::make_unsigned<double>’:
/usr/include/c++/11/type_traits:1925:11:   required by substitution of ‘template<class _Tp> using make_unsigned_t = typename std::make_unsigned::type [with _Tp = double]’
/usr/include/c++/11/numeric:173:13:   required from ‘constexpr std::common_type_t<_Mn, _Nn> std::gcd(_Mn, _Nn) [with _Mn = double; _Nn = int; std::common_type_t<_Mn, _Nn> = double]’
answer.code:28:25:   required from here
/usr/include/c++/11/type_traits:1786:62: error: invalid use of incomplete type ‘class std::__make_unsigned_selector<double, false, false>’
 1786 |     { typedef typename __make_unsigned_selector<_Tp>::__type type; };
      |                                                              ^~~~
/usr/include/c++/11/type_traits:1693:11: note: declaration of ‘class std::__make_unsigned_selector<double, false, false>’
 1693 |     class __make_unsigned_selector;
      |           ^~~~~~~~~~~~~~~~~~~~~~~~