foo.cc:2:7: error: expected nested-name-specifier before 'namespaec'
    2 | using namespaec std;
      |       ^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:6:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    6 |     cout <<  "A" << endl;
      |     ^~~~
      |     std::cout
iostream:61:18: note: 'std::cout' declared here
foo.cc:6:21: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    6 |     cout <<  "A" << endl;
      |                     ^~~~
      |                     std::endl
In file included from iostream:39:
/nix/store/h5kvfrjmpw792v8jg7nrzfkffmn0iyy8-gcc-12.3.0/include/c++/12.3.0/ostream:688:5: note: 'std::endl' declared here
  688 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~

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