Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  int m,n;
  int value=0;
  map<string,int> mp;
  
  cin >>m;
  for(int i=0;i<m;i++){
    string s;
    cin >>mp[s]++;
  }
  
  cin >>n;
  for(int i=0; i<n;i++){
    string s;
    cin >> mp[s]--;
  }
  
  for(auto it :mp){
    value=max(value,it.second);
  }
 cout << value << endl; 
}


Compiler output:
a.cc: In function 'int main()':
a.cc:12:9: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'})
   12 |     cin >>mp[s]++;
      |     ~~~ ^~
      |     |
      |     std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: 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>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'short int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:177:7: 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>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'short unsigned int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:184:7: 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>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'unsigned int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:188:7: 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>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'long int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:192:7: 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>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'long unsigned int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:199:7: 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>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'long long int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:203:7: 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>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'long long unsigned int&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:219:7: 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>]' (near match)
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'float&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:223:7: 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>]' (near match)
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'double&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: cannot bind non-const lvalue reference of type 'long double&' to a value of type 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'}
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: invalid conversion from 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'} to 'void*' [-fpermissive]
   12 |     cin >>mp[s]++;
a.cc:12:16: error: cannot bind rvalue '(void*)((long int)(mp.std::map<std::__cxx11::basic_string<char>, int>::operator[](s)++))' to 'void*&'
/usr/include/c++/14/istream:122:7: 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>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: invalid conversion from 'std::map<std::__cxx11::basic_string<char>, int>::mapped_type' {aka 'int'} to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
   12 |     cin >>mp[s]++;
/usr/include/c++/14/istream:126:7: 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>]' (near match)
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:7: note:   conversion of argument 1 would be ill-formed:
a.cc:12:16: error: invalid conversion from 'std::map<std::__cxx11::basic_string<char>, int>::mappe