#include <fstream>
#include <set>
using namespace std;
ifstream f("hashuri.in");
ofstream g("hashuri.out");
int n,op,x;
set <int> A;
int main()
{
    f >> n;
    for(int i=1; i<=n; i++)
    {
        f >> op >> x;
        if(op == 1)
        {
            A.insert(x);
            continue;
        }
        else if(op == 2)
        {
            A.erase(x);
            continue;
        }
        else if(op == 3)
            g << (A.find(x) != A.end()) << '\n';
    }

    g.close();
    return 0;
}