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