#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
#include <iostream>
#include <algorithm>
#include <queue>
#include <string>
#include <stack>
#define CLR(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
const int MAXN = 3 * 1e6 + 10;
const int MOD = 9973;
const int INF = 0x3f3f3f3f;
int sum;
struct Trie {
    int L, next[MAXN][30], root, word[MAXN], End[MAXN];
    int newnode() {
        for(int i = 0; i <= 25; i++) next[L][i] = -1;
        word[L] = 0; End[L] = 0; L++;
        return L-1;
    }
    void init() { L = 0; root = newnode(); }
    void Insert(char *s) {
        int u = root;
        for(int i = 0; s[i]; i++) {
            int v = s[i] - 'a';
            if(next[u][v] == -1)
                next[u][v] = newnode();
            u = next[u][v];
            word[u]++;
        }
        End[u]++;
    }
    void DFS(int u) {
        sum += End[u]; word[u] = 0; End[u] = 0;
        for(int i = 0; i <= 25; i++) {
            if(next[u][i] != -1) {
                DFS(next[u][i]);
                next[u][i] = -1;
            }
        }
    }
    void Delete(char *s) {
        int u = root; sum = 0;
        for(int i = 0; s[i]; i++) {
            int v = s[i] - 'a';
            if(next[u][v] == -1) return ;
            u = next[u][v];
        }
        DFS(u); u = root;
        for(int i = 0; s[i]; i++) {
            int v = s[i] - 'a';
            u = next[u][v];
            //cout << word[u] << endl;
            word[u] -= sum;
        }
        word[u] += sum;
    }
    bool Query(char *s) {
        int u = root;
        for(int i = 0; s[i]; i++) {
            int v = s[i] - 'a';
            u = next[u][v];
            //cout << word[u] << endl;
            if(word[u] == 0 || u == -1) return false;
        }
        return true;
    }
};
Trie T;
int main()
{
    int n;
    while(scanf("%d", &n) != EOF) {
        char op[10], str[100];
        T.init();
        while(n--) {
            scanf("%s%s", op, str);
            if(op[0] == 'i') {
                T.Insert(str);
            }
            else if(op[0] == 'd') {
                T.Delete(str);
            }
            else {
                printf(T.Query(str) ? "Yes\n" : "No\n");
            }
        }
    }
    return 0;
}