Language: C++

#include <bits/stdc++.h>
#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
typedef long long ll;
using namespace std;
const int MOD = 1000000007;
const int INF = 1010000000;
const double EPS = 1e-10;

int main(){
  int n;cin>>n;
  unordered_map<string,int> l;
  rep(i,n){
    string s;cin>>s;
    l[s]++;
  }
  int m;cin>>m;
  rep(i,n){
    string s;cin>>s;
    l[s]--;
  }
  int ans = 0;
  for(auto itr = l.begin();itr<l.end();itr++){
    ans = max(ans,itr->second
  }
  cout << ans << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:23:31: error: no match for 'operator<' (operand types are 'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' and 'std::unordered_map<std::__cxx11::basic_string<char>, int>::iterator' {aka 'std::__detail::_Insert_base<std::__cxx11::basic_string<char>, std::pair<const std::__cxx11::basic_string<char>, int>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, int> >, std::__detail::_Select1st, std::equal_to<std::__cxx11::basic_string<char> >, std::hash<std::__cxx11::basic_string<char> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true> >::iterator'})
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                            ~~~^~~~~~~~
      |                            |        |
      |                            |        _Node_iterator<[...],[...],[...]>
      |                            _Node_iterator<[...],[...],[...]>
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/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++/14/bits/regex.h:1143:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1224:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1317:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1391:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::unordered_map<std::__cxx11::basic_string<char>, int>::iterator' {aka 'std::__detail::_Insert_base<std::__cxx11::basic_string<char>, std::pair<const std::__cxx11::basic_string<char>, int>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, int> >, std::__detail::_Select1st, std::equal_to<std::__cxx11::basic_string<char> >, std::hash<std::__cxx11::basic_string<char> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true> >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1485:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1560:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::unordered_map<std::__cxx11::basic_string<char>, int>::iterator' {aka 'std::__detail::_Insert_base<std::__cxx11::basic_string<char>, std::pair<const std::__cxx11::basic_string<char>, int>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, int> >, std::__detail::_Select1st, std::equal_to<std::__cxx11::basic_string<char> >, std::hash<std::__cxx11::basic_string<char> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true> >::iterator'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/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++/14/bits/regex.h:1660:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1045:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator<(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1045 |     operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1045:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::pair<_T1, _T2>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:448:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  448 |     operator<(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:448:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::reverse_iterator<_Iterator>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/bits/stl_iterator.h:493:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  493 |     operator<(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:493:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::reverse_iterator<_Iterator>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1694 |     operator<(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note:   template argument deduction/substitution failed:
a.cc:23:38: note:   'std::__detail::_Node_iterator<std::pair<const std::__cxx11::basic_string<char>, int>, false, true>' is not derived from 'const std::move_iterator<_IteratorL>'
   23 |   for(auto itr = l.begin();itr<l.end();itr++){
      |                                      ^
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1760 |     operator<(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note:   template argument deduction/substitution failed:
a.cc:2