#include <bits/stdc++.h>
#define N 50001
#define pb push_back
#define INF 1<<30
using namespace std;
ifstream f("hashuri.in");
ofstream g("hashuri.out");
set <int> m;
int n,c,x;
int main()
{
    f>>n;
    while(n--)
    {
        f>>c>>x;
        if(c==1)
            m.insert(x);
        if(c==2)
            m.erase(x);
        if(c==3)
            g<<m.count(x)<<"\n";

    }
    return 0;
}