#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#define MAX 100100
#define mod 9973
using namespace std;
typedef long long LL;
char op[100], s[100];
struct Trie {
    int ch[30 * MAX][26];
    int val[30 * MAX];
    int self[30 * MAX];
    bool lazy[30 * MAX];
    int sz;
    Trie() {
        sz = 1;
        memset(ch[0], 0, sizeof(ch[0]));
        lazy[0] = false;
        val[0] = 0;
        self[0] = 0;
    }
    int idx(char c) { return c - 'a'; }
    void PushDown(int o) {
        if (lazy[o]) {
            for (int i = 0; i < 26; ++i) {
                if (!ch[o][i])
                    continue;
                lazy[ch[o][i]] = true;
                val[ch[o][i]] = 0;
                self[ch[o][i]] = 0;
            }
            lazy[o] = false;
        }
    }
    void PushUp(int o) {
        val[o] = self[o];
        for (int i = 0; i < 26; ++i) {
            if (!ch[o][i])
                continue;
            val[o] += val[ch[o][i]];
        }
    }
    void Insert(int u, int p, int n) {
        if (p == n) {
            self[u]++;
            val[u]++;
            return;
        }
        PushDown(u);
        int c = idx(s[p]);
        if (!ch[u][c]) {
            memset(ch[sz], 0, sizeof(ch[sz]));
            lazy[sz] = false;
            val[sz] = 0;
            ch[u][c] = sz++;
        }
        Insert(ch[u][c], p + 1, n);
        PushUp(u);
    }
    void insert(char *s) {
        int n = (int)strlen(s);
        Insert(0, 0, n);
    }
    void Del(int u, int p, int n) {
        if (p == n) {
            lazy[u] = true;
            val[u] = 0;
            self[u] = 0;
            return;
        }
        PushDown(u);
        int c = idx(s[p]);
        if (ch[u][c]) {
            Del(ch[u][c], p + 1, n);
        }
        PushUp(u);
    }
    void del(char *s) {
        int n = (int)strlen(s);
        Del(0, 0, n);
    }
    int Query(int u, int p, int n) {
        if (p == n)
            return val[u];
        PushDown(u);
        int c = idx(s[p]);
        int res = 0;
        if (ch[u][c]) {
            res = Query(ch[u][c], p + 1, n);
        }
        PushUp(u);
        return res;
    }
    int query(char *s) {
        int n = (int)strlen(s);
        return Query(0, 0, n);
    }
} trie;
int main() {
    int T;
    scanf("%d", &T);
    for (int t = 0; t < T; ++t) {
        scanf("%s", op);
        scanf("%s", s);
        switch (op[0]) {
        case 'i':
            trie.insert(s);
            break;
        case 'd':
            trie.del(s);
            break;
        case 's':
            printf("%s\n", trie.query(s) ? "Yes" : "No");
        default:
            break;
        }
    }
    return 0;
}