#include <iostream>
#include <fstream>
#include <set>

using namespace std;

ifstream f ("hashuri.in");
ofstream g ("hashuri.out");

int main()
{
    set <int> Set;
    int n;
    f >> n;
    for (int i = 1; i <= n; i++)
    {
        int option, x;
        f >> option >> x;
        switch (option)
        {
            case 1:
                Set.insert(x);
                break;
            case 2:
                Set.erase(x);
                break;
            case 3:
                g << Set.count(x) << "\n";
                break;
        }
    }
}