/in/foo.cc: In function 'int main()':
/in/foo.cc:68:12: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'Matrix3')
   68 |         cin>>m1>>m2>>m3;
      |         ~~~^~~~
      |         |    |
      |         |    Matrix3
      |         std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/12/iostream:40,
                 from /in/foo.cc:1:
/usr/include/c++/12/istream:120:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  120 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/12/istream:120:36: note:   no known conversion for argument 1 from 'Matrix3' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'}
  120 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/istream:124:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]'
  124 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/12/istream:124:32: note:   no known conversion for argument 1 from 'Matrix3' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  124 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/12/istream:131:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  131 |       operator>>(ios_base& (*__pf)(ios_base&))
      |       ^~~~~~~~
/usr/include/c++/12/istream:131:30: note:   no known conversion for argument 1 from 'Matrix3' to 'std::ios_base& (*)(std::ios_base&)'
  131 |       operator>>(ios_base& (*__pf)(ios_base&))
      |                  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~
/usr/include/c++/12/istream:168:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  168 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:168:24: note:   no known conversion for argument 1 from 'Matrix3' to 'bool&'
  168 |       operator>>(bool& __n)
      |                  ~~~~~~^~~
/usr/include/c++/12/istream:172:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  172 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/12/istream:172:25: note:   no known conversion for argument 1 from 'Matrix3' to 'short int&'
  172 |       operator>>(short& __n);
      |                  ~~~~~~~^~~
/usr/include/c++/12/istream:175:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  175 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:175:34: note:   no known conversion for argument 1 from 'Matrix3' to 'short unsigned int&'
  175 |       operator>>(unsigned short& __n)
      |                  ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/12/istream:179:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  179 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/12/istream:179:23: note:   no known conversion for argument 1 from 'Matrix3' to 'int&'
  179 |       operator>>(int& __n);
      |                  ~~~~~^~~
/usr/include/c++/12/istream:182:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  182 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:182:32: note:   no known conversion for argument 1 from 'Matrix3' to 'unsigned int&'
  182 |       operator>>(unsigned int& __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/12/istream:186:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  186 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:186:24: note:   no known conversion for argument 1 from 'Matrix3' to 'long int&'
  186 |       operator>>(long& __n)
      |                  ~~~~~~^~~
/usr/include/c++/12/istream:190:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  190 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:190:33: note:   no known conversion for argument 1 from 'Matrix3' to 'long unsigned int&'
  190 |       operator>>(unsigned long& __n)
      |                  ~~~~~~~~~~~~~~~^~~
/usr/include/c++/12/istream:195:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  195 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:195:29: note:   no known conversion for argument 1 from 'Matrix3' to 'long long int&'
  195 |       operator>>(long long& __n)
      |                  ~~~~~~~~~~~^~~
/usr/include/c++/12/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  199 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/12/istream:199:38: note:   no known conversion for argument 1 from 'Matrix3' to 'long long unsigned int&'
  199 |       operator>>(unsigned long long& __n)
      |                  ~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/12/istream:214:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  214 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/12/istream:214:25: note:   no known conversion for argument 1 from 'Matrix3' to 'float&'
  214 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/12/istream:218:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  218 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/12/istream:218:26: note:   no known conversion for argument 1 from 'Matrix3' to 'double&'
  218 |       operator>>(double& __f)
      |                  ~~~~~~~~^~~
/usr/i