#include <cstdio>
#include <set>

using namespace std;

#define file_in "hashuri.in"
#define file_out "hashuri.out"

int Q,Tip,X;
set<int> S;


int main(){
	
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d", &Q);
	
	while(Q--){
		
		scanf("%d %d", &Tip, &X);
		
		if (Tip==1){
			S.insert(X);
		}
		else
		if (Tip==2){
			S.erase(X);
		}
		else{
			printf("%d\n", S.find(X)!=S.end());
		}
    }

	return 0;
}