#include <bits/stdc++.h>
#pragma GCC optimize ("03")
#define FILES freopen("hashuri.in" , "r" , stdin) , freopen("hashuri.out" , "w" , stdout)
#define FastIO ios_base::sync_with_stdio(false) , cin.tie(0) , cout.tie(0)

using namespace std;

int op , x , n;
unordered_set < int > s;

signed main()
{
    FILES , FastIO;

    cin >> n;

    for(int i = 1 ; 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;
}