foo.cc:2:7: error: expected nested-name-specifier before 'namesapce'
 using namesapce std;
       ^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:5:2: error: 'cin' was not declared in this scope
  cin>>YY>>MM>>DD;
  ^~~
foo.cc:5:2: note: suggested alternative:
In file included from foo.cc:1:0:
/usr/include/c++/7/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^~~
foo.cc:5:7: error: 'YY' was not declared in this scope
  cin>>YY>>MM>>DD;
       ^~
foo.cc:5:11: error: 'MM' was not declared in this scope
  cin>>YY>>MM>>DD;
           ^~
foo.cc:5:15: error: 'DD' was not declared in this scope
  cin>>YY>>MM>>DD;
               ^~
foo.cc:6:2: error: 'cout' was not declared in this scope
  cout<<"2006-9-1"<<endl;
  ^~~~
foo.cc:6:2: 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
                  ^~~~
foo.cc:6:20: error: 'endl' was not declared in this scope
  cout<<"2006-9-1"<<endl;
                    ^~~~
foo.cc:6:20: note: suggested alternative:
In file included from /usr/include/c++/7/iostream:39:0,
                 from foo.cc:1:
/usr/include/c++/7/ostream:590:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^~~~