answer.code: In function ‘int main()’:
answer.code:51:13: error: no match for ‘operator<’ (operand types are ‘std::ostream’ {aka ‘std::basic_ostream<char>’} and ‘const char [3]’)
   51 |         cout<"N\n";
      |         ~~~~^~~~~~
      |         |    |
      |         |    const char [3]
      |         std::ostream {aka std::basic_ostream<char>}
In file included from /usr/include/c++/13/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:181,
                 from answer.code:1:
/usr/include/c++/13/bits/regex.h:1143:5: note: candidate: ‘template<class _BiIter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const sub_match<_BiIter>&)’
 1143 |     operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1143:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1224:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)’
 1224 |     operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1224:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1317:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)’
 1317 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1317:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1391:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)’
 1391 |     operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1391:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [3]’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1485:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)’
 1485 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1485:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1560:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)’
 1560 |     operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1560:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [3]’
   51 |         cout<"N\n";
      |              ^~~~~
/usr/include/c++/13/bits/regex.h:1660:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)’
 1660 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1660:5: note:   template argument deduction/substitution failed:
answer.code:51:14: note:   ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   51 |         cout<"N\n";
      |              ^~~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:64,
                 from /usr/include/c++/13/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51:
/usr/include/c++/13/bits/stl_pair.h:835:5: note: candidate: ‘template<class _T1, class _T2> constexpr bool std::operator<(const pair<_T1, _T2>&, const pair<_T1, _T2>&)’
  835 |     operator<(const pair<_T1, _T2>& __...