View Compilation Error

0_0_13376666_7438.cpp: In function 'int main()':
0_0_13376666_7438.cpp:105:19: error: could not convert 's.std::set<_Key, _Compare, _Alloc>::find<int, std::less<int>, std::allocator<int> >((*(const key_type*)(& num)))' from 'std::set<int>::iterator {aka std::_Rb_tree_const_iterator<int>}' to 'bool'