/in/foo.cc:6:6: error: 'vector' in namespace 'std' does not name a template type
    6 | std::vector<ll> compute_phi(ll N) {
      |      ^~~~~~
/in/foo.cc:3:1: note: 'std::vector' is defined in header '<vector>'; did you forget to '#include <vector>'?
    2 | #include <algorithm>
  +++ |+#include <vector>
    3 | 
/in/foo.cc: In function 'll solve(ll, ll)':
/in/foo.cc:36:10: error: 'vector' is not a member of 'std'
   36 |     std::vector<ll> phi = compute_phi(limit);
      |          ^~~~~~
/in/foo.cc:36:10: note: 'std::vector' is defined in header '<vector>'; did you forget to '#include <vector>'?
/in/foo.cc:36:19: error: expected primary-expression before '>' token
   36 |     std::vector<ll> phi = compute_phi(limit);
      |                   ^
/in/foo.cc:36:21: error: 'phi' was not declared in this scope
   36 |     std::vector<ll> phi = compute_phi(limit);
      |                     ^~~
/in/foo.cc:36:27: error: 'compute_phi' was not declared in this scope
   36 |     std::vector<ll> phi = compute_phi(limit);
      |                           ^~~~~~~~~~~