#include <cstdio>
#include <set>
using namespace std;
set<int>s;
int m;

int main(){
    int c,x;
    freopen("hashuri.in","r",stdin);
    freopen("hashuri.out","w",stdout);
        scanf("%d",&m);
        for(int i=1;i<=m;i++){
            scanf("%d %d",&c,&x);
            switch(c){
                case 1: s.insert(x); break;
                case 2: s.erase(x); break;
                case 3: printf("%d\n",s.find(x)!=s.end());  }
        }
}