#include <fstream>
#include <set>

using namespace std;

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

int n;
int op, x;
set<int> s;
int i;

int main()
{
    fin >>n;
    for (i = 1; i <= n; ++i)
    {
        fin >>op>>x;
        switch(op)
        {
        case 1:
            s.insert(x);
            break;

        case 2:
            s.erase(x);
            break;

        case 3:
            fout <<(s.find(x) != s.end())<<'\n';
            break;
        }
    }

    fout.close();
    return 0;
}