#include <fstream>
#include <set>
using namespace std;
ifstream cin( "hash.in" );
ofstream cout( "hash.out" );

int n, op, x;
set<int> a;
int main()
{
	int i;
	cin >> n;
	for ( i = 1; i <= n; i++ )
	{
		cin >> op >> x;
		if ( op == 1 ) a.insert( x );
		else if ( op == 2 ) a.erase( x );
		else cout << ( a.find( x ) != a.end() ) << '\n';
	}
}