View Compilation Error

0_0_37183834_28442.cpp: In function 'int main()':
0_0_37183834_28442.cpp:47:16: error: could not convert 'b.std::set<_Key, _Compare, _Alloc>::find<int, std::less<int>, std::allocator<int> >((*(const key_type*)(& first)))' from 'std::set<int>::iterator {aka std::_Rb_tree_const_iterator<int>}' to 'bool'
    if(b.find(x))puts("YES");
                ^