#include <bits/stdc++.h>

using namespace std;

unordered_set <int> st;

int main() {
    ifstream fin( "hashuri.in" );
    ofstream fout( "hashuri.out" );
    int n;
    fin >> n;
    for ( int i = 1, tip, x; i <= n; i ++ ) {
        fin >> tip >> x;
        if ( tip == 1 ) {
            st.insert( x );
        } else if ( tip == 2 ) {
            st.erase( x );
        } else {
            fout << st.count( x ) << '\n';
        }
    }
    return 0;
}