Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:43:16: error: could not convert ‘A.std::multiset<_Key, _Compare, _Alloc>::find<long int, std::less<long int>, std::allocator<long int> >((* &((std::multiset<long int>::key_type)x)))’ from ‘std::multiset<long int>::iterator {aka std::_Rb_tree_const_iterator<long int>}’ to ‘bool’ if(A.find(x))A.insert(x); ^