answer.code:17:18: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   17 | auto &operator<<(auto &o, pair<auto, auto> p) {
      |                  ^~~~
answer.code:17:32: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   17 | auto &operator<<(auto &o, pair<auto, auto> p) {
      |                                ^~~~
answer.code:17:38: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   17 | auto &operator<<(auto &o, pair<auto, auto> p) {
      |                                      ^~~~
answer.code:21:17: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   21 | auto operator<<(auto &o, auto x)->decltype(end(x), o) {
      |                 ^~~~
answer.code:21:26: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   21 | auto operator<<(auto &o, auto x)->decltype(end(x), o) {
      |                          ^~~~
answer.code:97:14: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   97 |     auto fix(auto it) { return it == end() ? begin() : it; }
      |              ^~~~
answer.code:98:18: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   98 |     auto getNext(auto it) { return fix(next(it)); }
      |                  ^~~~
answer.code:99:18: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   99 |     auto getPrev(auto it) {
      |                  ^~~~
answer.code:103:20: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
  103 |     auto crossNext(auto it) {
      |                    ^~~~
answer.code:107:14: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
  107 |     auto del(auto it) {
      |              ^~~~
answer.code: In lambda function:
answer.code:158:74: error: ‘pole’ was not declared in this scope
  158 |             T I = ((g - a).dist2() + (g - b).dist2() + (g - c).dist2()) *pole/ 12;
      |                                                                          ^~~~