#include <cstdio>
#include <set>

using namespace std;

int i, n, tmp, t, x;
set <int> S;

int main()
{
    freopen ("hashuri.in", "r", stdin);
    freopen ("hashuri.out", "w", stdout);
    scanf ("%d", &n);
    for (i=1; i<=n; i++)
    {
        scanf ("%d%d", &t, &x);
        if (t==1) S.insert(x);
        if (t==2) S.erase(x);
        if (t==3) printf ("%d\n", S.find(x)!=S.end());
    }
}