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

fstream fin("hashuri.in");
ofstream fout("hashuri.out");

unordered_set<int> us;
int n;

int main()
{
    int i, type, x;
    fin>>n;

    for(i = 1; i <= n; ++i){
        fin>>type>>x;

        if(type == 1)
            us.insert(x);
        else{
            if(type == 2)
                us.erase(x);
            else
                fout<<us.count(x)<<"\n";
        }
    }
    return 0;
}