#include <iostream>
#include <fstream>
#include <unordered_set>

std::unordered_set<int> hs;

int main() {
  std::ifstream in("hashuri.in");
  std::ofstream out("hashuri.out");

  int n;
  in >> n;

  int op, a;

  for (int i = 1; i <= n; ++i) {
    in >> op >> a;

    if (op == 1)
      hs.insert(a);
    else if (op == 2)
      hs.erase(a);
    else
      out << hs.count(a) << '\n';
  }

  return 0;
}