#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;

struct PrefixTreeNode {
    int wordPrefixedCount;
    bool existsExactWord;
    PrefixTreeNode* next[26];
    PrefixTreeNode() { memset(this, 0, sizeof(PrefixTreeNode)); }
    bool insert(const char* word)//duplicated?
    {
        ++wordPrefixedCount;
        bool ret;
        if (*word != '\0') {
            if (!next[*word - 'a']) next[*word - 'a'] = new PrefixTreeNode();
            ret = next[*word - 'a']->insert(word + 1);
            if (ret) --wordPrefixedCount;
        }
        else {
            ret = existsExactWord;
            existsExactWord = true;
        }
        return ret;
    }
    int deleteWord(const char* word)
    {
        int ret = 0;
        if (*word == '\0') {
            ret = wordPrefixedCount;
            memset(this, 0, sizeof(PrefixTreeNode));
        }
        else if (next[*word - 'a']) {
            ret = next[*word - 'a']->deleteWord(word + 1);
            wordPrefixedCount -= ret;
        }
        return ret;
    }
    bool search(const char* word)
    {
        if (*word == '\0') return wordPrefixedCount > 0;
        if (!next[*word - 'a']) return false;
        return next[*word - 'a']->search(word + 1);
    }
};


int main()
{
    int T;
    cin >> T;
    PrefixTreeNode root;
    while (T--)
    {
        char op[10], word[32];
        scanf("%s %s", op, word);
        switch (op[0])
        {
        case 'i':
            root.insert(word);
            break;
        case 'd':
            root.deleteWord(word);
            break;
        case 's':
            printf(root.search(word) ? "Yes\n" : "No\n");
            break;
        }

    }
#ifndef ONLINE_JUDGE
    system("pause");
#endif
    return 0;
}