/in/foo.cc: In function 'int main()':
/in/foo.cc:20:9: error: 'cin' was not declared in this scope
   20 |         cin>>l>>r;
      |         ^~~
/in/foo.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    2 | #include<cstdio>
  +++ |+#include <iostream>
    3 | using namespace std;
/in/foo.cc:23:9: error: 'cout' was not declared in this scope
   23 |         cout<<ans;
      |         ^~~~
/in/foo.cc:23:9: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?