#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <iterator>
#include <string>
#include <string.h>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <sstream>
#include <cstring>
#include <cstdlib>
#include <stdlib.h>
#include <stdio.h>
#include <cstdio>
#include <queue>
#define forn(i,n) for(int i=0;i<n;i++)
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
typedef vector<string>::iterator iter;

vector<string> lib[26];

iter fin(iter s,iter f,char* x)
{
    iter it;
    int len=strlen(x);
    for(it=s; it!=f; it++)
        if((*it).size()>=len) {
            int p=1;
            for(int i=0; i<len; i++)
                if(x[i]!=(*it)[i]) {
                    p=0;
                    break;
                }
            if(p)return it;
        }
    return it;
}

void ins(char* x)
{
    lib[x[0]-'a'].push_back(x);
}

void del(char* x)
{
    int pos=x[0]-'a';
    iter it=lib[pos].begin();
    for(;;) {
        it=fin(it,lib[pos].end(),x);
        if(it==lib[pos].end())break;
//        cout<<*it<<endl;
        it=lib[pos].erase(it);
    }
}

bool sea(char* x)
{
    int pos=x[0]-'a';
    iter it=lib[pos].begin();
    it=fin(it,lib[pos].end(),x);
    if(it==lib[pos].end())return false;
//        cout<<*it<<endl;
    return true;
}



int main()
{
#ifndef ONLINE_JUDGE
    //freopen("in.txt","r",stdin);
#endif // ONLINE_JUDGE
    //freopen("out.txt","w",stdout);
    int n;
    char cmd[10],x[100];
    cin>>n;
    while(n--) {
        scanf("%s%s",cmd,x);
        if(cmd[0]=='i') {
            ins(x);//insert
        } else if(cmd[0]=='d') {
            del(x);//delete
        } else if(cmd[0]=='s') {
            cout<<(sea(x)?"Yes\n":"No\n");
        }
    }
    return 0;
}