answer.code: In function ‘int main()’:
answer.code:16:9: error: ‘cin’ was not declared in this scope
   16 |         cin >> n;
      |         ^~~
answer.code:5:1: note: ‘std::cin’ is defined in header ‘<iostream>’; did you forget to ‘#include <iostream>’?
    4 | #include<string.h>
  +++ |+#include <iostream>
    5 | using namespace std;
answer.code:21:25: error: ‘cout’ was not declared in this scope
   21 |                         cout << i;
      |                         ^~~~
answer.code:21:25: note: ‘std::cout’ is defined in header ‘<iostream>’; did you forget to ‘#include <iostream>’?
answer.code:25:9: error: ‘cout’ was not declared in this scope
   25 |         cout << "impossible";
      |         ^~~~
answer.code:25:9: note: ‘std::cout’ is defined in header ‘<iostream>’; did you forget to ‘#include <iostream>’?