#include<set>
#include<fstream>
using namespace std;

int main()
{
    ifstream fin("hashuri.in");
    ofstream fout("hashuri.out");
    int nOp; fin>>nOp;
    set<int> M;
    for (int i=1;i<=nOp;i++)
    {
        int op, val;
        fin>>op>>val;
        switch (op)
        {
            case 1: M.insert(val); break;
            case 2: M.erase(val); break;
            case 3: fout<<M.count(val)<<'\n';
        }
    }
    return 0;
}