answer.code:4:15: error: ‘acosl’ was not declared in this scope
    4 | const db pi = acosl(-1);
      |               ^~~~~
answer.code: In member function ‘db P2::abs() const’:
answer.code:13:29: error: ‘sqrtl’ was not declared in this scope
   13 |     db abs() const { return sqrtl(x * x + y * y); } // sqrtl
      |                             ^~~~~
answer.code: In member function ‘db P2::arg() const’:
answer.code:14:29: error: ‘atan2l’ was not declared in this scope
   14 |     db arg() const { return atan2l(y, x); } // atan2l
      |                             ^~~~~~
answer.code: In function ‘P2 read()’:
answer.code:33:5: error: ‘cin’ was not declared in this scope
   33 |     cin >> x >> y;
      |     ^~~
answer.code: In function ‘db point_to_line(P2, Line)’:
answer.code:60:12: error: ‘abs’ was not declared in this scope
   60 |     return abs(l.p * (a - l.s)) / dis(l.s, l.t);
      |            ^~~
answer.code: In function ‘P2 rotate(P2, db)’:
answer.code:78:21: error: ‘cos’ was not declared in this scope
   78 |     return P2(a.x * cos(t) - a.y * sin(t),
      |                     ^~~
answer.code:78:36: error: ‘sin’ was not declared in this scope; did you mean ‘sgn’?
   78 |     return P2(a.x * cos(t) - a.y * sin(t),
      |                                    ^~~
      |                                    sgn
answer.code: In function ‘db point_to_segment(P2, Line)’:
answer.code:116:12: error: ‘min’ was not declared in this scope
  116 |     return min(dis(a, l.s), dis(a, l.t));
      |            ^~~