Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  set<int> st;
  int n,m,a=0,b=0;
  cin>>n;
  vector<string> v(n);
  
  for(int i=0;i<n;i++) cin>>v[i];
  cin>>m;
  vector<string> w(m);
  for(int i=0;i<m;i++) cin>>w[i];
  
  for(int i=0;i<n;i++) st.insert(v[i]);
  for(int i=0;i<st.size();i++){
    for(int j=0;j<n;j++){
      if(st[i]==v[j]){
        b++;
      }
    }
    for(int j=0;j<m;j++){
      if(st[i]==w[j]){
        b--;
      }
    }
    a=max(a,b);
    b=0;
  }
  cout<<a<<endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:33: error: no matching function for call to 'std::set<int>::insert(__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type&)'
   14 |   for(int i=0;i<n;i++) st.insert(v[i]);
      |                        ~~~~~~~~~^~~~~~
In file included from /usr/include/c++/14/set:63,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:158,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_set.h:568:9: note: candidate: 'template<class _InputIterator> void std::set<_Key, _Compare, _Alloc>::insert(_InputIterator, _InputIterator) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>]'
  568 |         insert(_InputIterator __first, _InputIterator __last)
      |         ^~~~~~
/usr/include/c++/14/bits/stl_set.h:568:9: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_set.h:511:7: note: candidate: 'std::pair<typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator, bool> std::set<_Key, _Compare, _Alloc>::insert(const value_type&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other = std::allocator<int>; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key> = __gnu_cxx::__alloc_traits<std::allocator<int>, int>::rebind<int>; typename _Alloc::value_type = int; value_type = int]'
  511 |       insert(const value_type& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:511:32: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'const std::set<int>::value_type&' {aka 'const int&'}
  511 |       insert(const value_type& __x)
      |              ~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_set.h:520:7: note: candidate: 'std::pair<typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator, bool> std::set<_Key, _Compare, _Alloc>::insert(value_type&&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other = std::allocator<int>; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key> = __gnu_cxx::__alloc_traits<std::allocator<int>, int>::rebind<int>; typename _Alloc::value_type = int; value_type = int]'
  520 |       insert(value_type&& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:520:27: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'std::set<int>::value_type&&' {aka 'int&&'}
  520 |       insert(value_type&& __x)
      |              ~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_set.h:548:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::insert(const_iterator, const value_type&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; const_iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; value_type = int]'
  548 |       insert(const_iterator __position, const value_type& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:548:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_set.h:553:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::insert(const_iterator, value_type&&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; const_iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; value_type = int]'
  553 |       insert(const_iterator __position, value_type&& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:553:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_set.h:580:7: note: candidate: 'void std::set<_Key, _Compare, _Alloc>::insert(std::initializer_list<_Tp>) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>]'
  580 |       insert(initializer_list<value_type> __l)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:580:43: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'std::initializer_list<int>'
  580 |       insert(initializer_list<value_type> __l)
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_set.h:600:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::insert_return_type std::set<_Key, _Compare, _Alloc>::insert(node_type&&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; insert_return_type = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::insert_return_type; node_type = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::node_type]'
  600 |       insert(node_type&& __nh)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:600:26: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'std::set<int>::node_type&&' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::node_type&&'}
  600 |       insert(node_type&& __nh)
      |              ~~~~~~~~~~~~^~~~
/usr/include/c++/14/bits/stl_set.h:605:7: note: candidate: 'std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::insert(const_iterator, node_type&&) [with _Key = int; _Compare = std::less<int>; _Alloc = std::allocator<int>; iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; const_iterator = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator; node_type = std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::node_type]'
  605 |       insert(const_iterator __hint, node_type&& __nh)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_set.h:605:7: note:   candidate expects 2 arguments, 1 provided
a.cc:17:12: error: no match for 'operator[]' (operand types are 'std::set<int>' and 'int')
   17 |       if(st[i]==v[j]){
      |            ^
a.cc:22:12: error: no match for 'operator[]' (operand types are 'std::set<int>' and 'int')
   22 |       if(st[i]==w[j]){
      |            ^