foo.cc: In function 'int main()':
foo.cc:4:36: error: 'cin' was not declared in this scope
    4 | long long a,b,year;long long cnt=0;cin>>a>>b;
      |                                    ^~~
foo.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;
foo.cc:10:1: error: 'cout' was not declared in this scope
   10 | cout<<cnt<<endl;
      | ^~~~
foo.cc:10:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
foo.cc:10:12: error: 'endl' was not declared in this scope
   10 | cout<<cnt<<endl;
      |            ^~~~
foo.cc:1:1: note: 'std::endl' is defined in header '<ostream>'; did you forget to '#include <ostream>'?
  +++ |+#include <ostream>
    1 | using namespace std;

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