#include <cstdio>
#include <set>
using namespace std;

int main ()
{set<int> S;
 int n,x,op;
 freopen("hashuri.in","r",stdin);
 freopen("hashuri.out","w",stdout);
 scanf("%d",&n);
 for (int i=1;i<=n;i++)
 {scanf("%d %d",&op,&x);
  switch(op)
  {case 1:S.insert(x);break;
   case 2:S.erase(x);break;
   case 3:printf("%d\n",S.count(x));break;
  }
 }
 return 0;
}