#include<fstream>
#include<set>
using namespace std;
set <int> s;
int n,t,x;
ifstream in("hashuri.in"); ofstream out("hashuri.out");
int main(){
    in>>n;
    for(int i=1;i<=n;++i){
        in>>t>>x; //Versiunea 1: set!
        switch(t){
            case 1:{s.insert(x);break;};
            case 2:{s.erase(x); break;};
            case 3:{out<<s.count(x)<<'\n';break;};
        };
    }
    out.close();
    return 0;
}