foo.cc:2:7: error: expected nested-name-specifier before 'nanespace'
 using nanespace std;
       ^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:5:1: error: 'cout' was not declared in this scope
 cout<<"Hello World!";
 ^~~~
foo.cc:5:1: note: suggested alternative:
In file included from foo.cc:1:0:
/usr/include/c++/7/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~

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