answer.code: In function ‘void solve()’:
answer.code:126:30: error: use of deleted function ‘std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = std::array<long int, 2>; _Hash = std::hash<std::array<long int, 2> >; _Pred = std::equal_to<std::array<long int, 2> >; _Alloc = std::allocator<std::array<long int, 2> >]’
  126 |         set <array <int, 2>> stk;
      |                              ^~~
In file included from /usr/include/c++/11/unordered_set:47,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:118,
                 from answer.code:1:
/usr/include/c++/11/bits/unordered_set.h:135:7: note: ‘std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = std::array<long int, 2>; _Hash = std::hash<std::array<long int, 2> >; _Pred = std::equal_to<std::array<long int, 2> >; _Alloc = std::allocator<std::array<long int, 2> >]’ is implicitly deleted because the default definition would be ill-formed:
  135 |       unordered_set() = default;
      |       ^~~~~~~~~~~~~
/usr/include/c++/11/bits/unordered_set.h:135:7: error: use of deleted function ‘std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::array<long int, 2>; _Value = std::array<long int, 2>; _Alloc = std::allocator<std::array<long int, 2> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<long int, 2> >; _Hash = std::hash<std::array<long int, 2> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]’
In file included from /usr/include/c++/11/unordered_map:46,
                 from /usr/include/c++/11/functional:61,
                 from /usr/include/c++/11/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/11/algorithm:74,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:65,
                 from answer.code:1:
/usr/include/c++/11/bits/hashtable.h:528:7: note: ‘std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::array<long int, 2>; _Value = std::array<long int, 2>; _Alloc = std::allocator<std::array<long int, 2> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<long int, 2> >; _Hash = std::hash<std::array<long int, 2> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]’ is implicitly deleted because the default definition would be ill-formed:
  528 |       _Hashtable() = default;
      |       ^~~~~~~~~~
/usr/include/c++/11/bits/hashtable.h:528:7: error: use of deleted function ‘std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::array<long int, 2>; _Value = std::array<long int, 2>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<long int, 2> >; _Hash = std::hash<std::array<long int, 2> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]’
In file included from /usr/include/c++/11/bits/hashtable.h:35,
                 from /usr/include/c++/11/unordered_map:46,
                 from /usr/include/c++/11/functional:61,
                 from /usr/include/c++/11/pstl/glue_algorithm_defs.h:13,
                 from /usr/include/c++/11/algorithm:74,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:65,
                 from answer.code:1:
/usr/include/c++/11/bits/hashtable_policy.h:1604:7: note: ‘std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::array<long int, 2>; _Value = std::array<long int, 2>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<long int, 2> >; _Hash = std::hash<std::array<long int, 2> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]’ is implicitly deleted because the default definition would be ill-formed:
 1604 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/11/bits/hashtable_policy.h:1604:7: error: use of deleted function ‘std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = std::array<long int, 2>; _Value = std::array<long int, 2>; _ExtractKey = std::__detail::_Identity; _Hash = std::hash<std::array<long int, 2> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_range...