/in/foo.cc: In function 'bool cmp(stu, stu)':
/in/foo.cc:10:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |         return x.ch>y.ch||x.ch==y.ch&&x.ma>y.ma;
      |                           ~~~~~~~~~~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:18:28: error: request for member 'xh' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   18 |                 cin>>st[i].xh>>st[i].ch>>st[i].ma;
      |                            ^~
/in/foo.cc:18:38: error: request for member 'ch' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   18 |                 cin>>st[i].xh>>st[i].ch>>st[i].ma;
      |                                      ^~
/in/foo.cc:18:48: error: request for member 'ma' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   18 |                 cin>>st[i].xh>>st[i].ch>>st[i].ma;
      |                                                ^~
/in/foo.cc:21:29: error: request for member 'xh' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   21 |                 cout<<st[i].xh<<' '<<st[i].ch<<' '<<st[i].ma<<endl;
      |                             ^~
/in/foo.cc:21:44: error: request for member 'ch' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   21 |                 cout<<st[i].xh<<' '<<st[i].ch<<' '<<st[i].ma<<endl;
      |                                            ^~
/in/foo.cc:21:59: error: request for member 'ma' in 'st.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   21 |                 cout<<st[i].xh<<' '<<st[i].ch<<' '<<st[i].ma<<endl;
      |                                                           ^~
In file included from /usr/include/c++/12/bits/stl_algobase.h:71,
                 from /usr/include/c++/12/string:50,
                 from /usr/include/c++/12/bits/locale_classes.h:40,
                 from /usr/include/c++/12/bits/ios_base.h:41,
                 from /usr/include/c++/12/ios:42,
                 from /usr/include/c++/12/istream:38,
                 from /usr/include/c++/12/sstream:38,
                 from /usr/include/c++/12/complex:45,
                 from /usr/include/c++/12/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:54,
                 from /in/foo.cc:1:
/usr/include/c++/12/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Iter_comp_iter<_Compare>::operator()(_Iterator1, _Iterator2) [with _Iterator1 = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; _Iterator2 = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; _Compare = bool (*)(stu, stu)]':
/usr/include/c++/12/bits/stl_algo.h:1809:14:   required from 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1849:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1940:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:4853:18:   required from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = bool (*)(stu, stu)]'
/in/foo.cc:19:6:   required from here
/usr/include/c++/12/bits/predefined_ops.h:158:30: error: could not convert '__it1.__gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator*()' from 'int' to 'stu'
  158 |         { return bool(_M_comp(*__it1, *__it2)); }
      |                       ~~~~~~~^~~~~~~~~~~~~~~~
      |                              |
      |                              int
/usr/include/c++/12/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Val_comp_iter<_Compare>::operator()(_Value&, _Iterator) [with _Value = int; _Iterator = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; _Compare = bool (*)(stu, stu)]':
/usr/include/c++/12/bits/stl_algo.h:1789:20:   required from 'void std::__unguarded_linear_insert(_RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Val_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1817:36:   required from 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1849:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1940:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:4853:18:   required from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = bool (*)(stu, stu)]'
/in/foo.cc:19:6:   required from here
/usr/include/c++/12/bits/predefined_ops.h:240:30: error: could not convert '__val' from 'int' to 'stu'
  240 |         { return bool(_M_comp(__val, *__it)); }
      |                       ~~~~~~~^~~~~~~~~~~~~~
      |                              |
      |                              int
/usr/include/c++/12/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Iter_comp_val<_Compare>::operator()(_Iterator, _Value&) [with _Iterator = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; _Value = int; _Compare = bool (*)(stu, stu)]':
/usr/include/c++/12/bits/stl_heap.h:140:48:   required from 'void std::__push_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare&) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Distance = long int; _Tp = int; _Compare = __gnu_cxx::__ops::_Iter_comp_val<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_heap.h:247:23:   required from 'void std::__adjust_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Distance = long int; _Tp = int; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_heap.h:356:22:   required from 'void std::__make_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(stu, stu)>]'
/usr/include/c++/12/bits/stl_algo.h:1629:23:   required from 'void std::__heap_select(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<int*, vector<int> >; _Compare = __gnu_cxx::__