#include <fstream>
#include <map>
#define file "hashuri"

using namespace std;

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

int n,p,x;

map<int,bool> h;

int main()
{
    fin>>n;
    while(n--)
    {
        fin>>p>>x;
        if(p == 1) h.insert(pair<int,bool>(x,1));
        else if(p == 2) h.erase(x);
        else fout<<h[x]<<"\n";
    }

    return 0;
}