#include <fstream>
#include <unordered_set>

int main(){
    std::ifstream fin("hashuri.in");
    std::ofstream fout("hashuri.out");

    std::unordered_set<unsigned> s;
    unsigned n;
    fin>>n;
    while(n--){
        char c; unsigned u;
        fin>>c>>u;
        if(c=='1') s.insert(u);
        else{
            auto i=s.find(u);
            if(i==s.end()){
                if(c=='3') fout<<0<<'\n';
            }
            else{
                if(c=='3') fout<<1<<'\n';
                else s.erase(i);
            }
        }
    }
}