/in/foo.cc:2:7: error: expected nested-name-specifier before 'namespaec'
 using namespaec std;
       ^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:5: error: 'cout' was not declared in this scope
     cout <<  "A" << endl;
     ^~~~
/in/foo.cc:6:5: note: suggested alternative:
In file included from /in/foo.cc:1:0:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
/in/foo.cc:6:21: error: 'endl' was not declared in this scope
     cout <<  "A" << endl;
                     ^~~~
/in/foo.cc:6:21: note: suggested alternative:
In file included from /usr/include/c++/6/iostream:39:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/ostream:590:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^~~~