#define BE(v) v.begin(), v.end()

template < class iter >
void view(iter b, iter e) {
  iter it;
  for (it=b;it!=e;it++) {
    cout << *it << " ";
  }
  cout << "\n";
}

template<class T>
void Sunion(set<T> &a, set<T> b, set<T> c) {
a.clear();
set_union(BE(b),BE(c),inserter(a,a.begin()));
}

template<class T>
void Sintersection(set<T> &a, set<T> b, set<T> c) {
a.clear();
set_intersection(BE(b),BE(c),inserter(a,a.begin()));
}