#include <fstream>
#include <unordered_set>
using namespace std;
ifstream cin("hashuri.in");
ofstream cout("hashuri.out");
unordered_set <int> mp;
int main()
{
    int n,i,x,op;
    cin >> n;
    for(i = 1;i <= n;i++){
        cin >> op >> x;
        if(op == 1){
            mp.insert(x);
        }else if(op == 2){
            mp.erase(x);
        }else{
            cout << (mp.find(x) != mp.end()) << "\n";
        }
    }
    return 0;
}