#include <fstream>
#include <set>

int main()
{
  std::set<int> set;
  std::ifstream f("hashuri.in");
  std::ofstream g("hashuri.out");
  int op, x, n;
  
  f >> n;
  for (int i = 0; i < n; ++i)
  {
    f >> op >> x;
    
    switch (op)
    {
    case 1:
    {
      set.insert(x);
    }
      break;
    
    case 2:
    {
      set.erase(x);
    }
      break;
    
    case 3:
    {
      g << set.count(x) << '\n';
    }
      break;

    default:
      break;
    }
  }
  
  return 0;
}