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

using namespace std;

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

unordered_set <int> Hashuri;

int main()
{
	int n,op,nr;
	f >> n;
	for (int i = 1; i <= n; i++)
	{
		f >> op >> nr;
		if (op == 1)
		{
			Hashuri.insert(nr);
		}
		else if (op == 2)
		{
			Hashuri.erase(nr);
		}
		else {
			g << Hashuri.count(nr) << '\n';
		}
	}
}