#include <cstdio>
#include <unordered_set>
using namespace std;
int n, t, x;
unordered_set<int>st;
FILE *fin=fopen("hashuri.in","r");
FILE *fout=fopen("hashuri.out","w");
int main()
{
    fscanf(fin,"%d",&n);
    for (int i=1;i<=n;++i)
    {
        fscanf(fin,"%d %d",&t,&x);
        if (t == 1)
            st.insert(x);
        else
        if (t == 2)
            st.erase(x);
        else
            fprintf(fout,"%d\n",st.count(x));
    }
    return 0;
}