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

using namespace std;

ifstream fin("hashuri.in");
ofstream fout("hashuri.out");

unordered_set<int> hashish;

int main()
{
    int n;
    fin>>n;
    for (int i=0; i < n; i++)
    {
        int x,op;
        fin>>op>>x;
        switch (op){
            case 1: hashish.insert(x);
                    break;
            case 2: hashish.erase(x);
                    break;
            case 3: fout<<hashish.count(x)<<"\n";
        }
    }
    return 0;
}