Language: C++

#include<bits/stdc++.h>
using namespace st;
#define r(i,n) for(int i=0;i<n;i++)
int main(){
  string a,b;
  int sum=0;
  cin>>a>>b;a+=b;
  r(i,a.size())sum=sum*10+(a[i]-'0');
  for(int i=0;i<10000;i++){
    if(i*i==sum){
      cout<<"Yes"<<endl;
      return 0;
    }
  }
  cout<<"No"<<endl;
}

Compiler output:
a.cc:2:17: error: 'st' is not a namespace-name
    2 | using namespace st;
      |                 ^~
a.cc: In function 'int main()':
a.cc:5:3: error: 'string' was not declared in this scope
    5 |   string a,b;
      |   ^~~~~~
a.cc:5:3: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:7:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    7 |   cin>>a>>b;a+=b;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:7:8: error: 'a' was not declared in this scope
    7 |   cin>>a>>b;a+=b;
      |        ^
a.cc:7:11: error: 'b' was not declared in this scope
    7 |   cin>>a>>b;a+=b;
      |           ^
a.cc:11:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |       cout<<"Yes"<<endl;
      |       ^~~~
      |       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:11:20: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |       cout<<"Yes"<<endl;
      |                    ^~~~
      |                    std::endl
In file included from /usr/include/c++/14/istream:41,
                 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:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:15:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   15 |   cout<<"No"<<endl;
      |   ^~~~
      |   std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:15:15: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   15 |   cout<<"No"<<endl;
      |               ^~~~
      |               std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~