#include <fstream>
#include <set>

using namespace std;

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

set<int> s;
int n, c, x;
int main()
{
    f>>n;
    for(;n;n--)
    {
        f>>c>>x;
        if(c==1)
            s.insert(x);
        else
        if(c==2)
            s.erase(x);
        else
            g<<(s.find(x)!=s.end())<<'\n';
    }
    return 0;
}