#include<cstdio>
#include<tr1/unordered_set>
using namespace std::tr1;

unordered_set<int> hs;
int main()
{
	freopen ("hashuri.in","r",stdin);
	freopen ("hashuri.out","w",stdout);
	int n;
	scanf ("%d",&n);
	while(n--){
		int x,y;
		scanf ("%d %d",&x,&y);
		switch(x){
		case 1:
			hs.insert (y);
			break;
		case 2:
			hs.erase (y);
			break;
		case 3:
			printf ("%lu\n",hs.count (y));
			break;
		}
	}
	return 0;
}