#include <cstdio>
#include <cstring>
const int maxc = 3000005;
int n;
struct trie
{
    char ch[maxc];
    int head[maxc], next[maxc];
    int val[maxc];
    int nodes;
    trie(): nodes(0)
    {
        memset(ch, 0, sizeof ch);
        memset(head, 0, sizeof head);
        memset(next, 0, sizeof next);
    }
    void insert(char *c)
    {
        int cur = 0;
        for (int i = 0; c[i] != '\0'; i++)
        {
            int nex;
            for (nex = head[cur]; nex; nex = next[nex])
                if (ch[nex] == c[i])
                    break;
            if (!nex)
            {
                nex = ++nodes;
                ch[nex] = c[i];
                next[nex] = head[cur];
                head[cur] = nex;
                val[nex] = 1;
            }
            cur = nex;
            val[cur]++;
        }
    }
    void remove(char *c)
    {
        int cur = 0;
        for (int i = 0; c[i] != '\0'; i++)
        {
            int nex;
            for (nex = head[cur]; nex; nex = next[nex])
                if (ch[nex] == c[i])
                    break;
            if (!nex)
                return;
            cur = nex;
        }
        ch[cur] = '$';
        update(c, val[cur]);
    }
    void update(char *c, int d)
    {
        int cur = 0;
        for (int i = 0; c[i] != '\0'; i++)
        {
            int nex;
            for (nex = head[cur]; nex; nex = next[nex])
                if (ch[nex] == c[i])
                    break;
            cur = nex;
            val[cur] -= d;
        }
    }
    bool search(char *c)
    {
        int cur = 0;
        for (int i = 0; c[i] != '\0'; i++)
        {
            int nex;
            for (nex = head[cur]; nex; nex = next[nex])
                if (ch[nex] == c[i])
                    break;
            if (!nex)
                return false;
            cur = nex;
        }
        return val[cur] > 0 ? true : false;
    }
    void print()
    {
        for (int i = 0; i <= nodes; i++)
            printf("%c ", ch[i]);
        printf("\n");
        printf("next[]=");
        for (int i = 0; i <= nodes; i++)
            printf("%d ", next[i]);
        printf("\n");
        printf("head[]=");
        for (int i = 0; i <= nodes; i++)
            printf("%d ", head[i]);
        printf("\n");
    }
};
trie sol;
int main()
{
//    freopen("C.in", "r", stdin);
//    freopen("C.out", "w", stdout);
    scanf("%d", &n);
    char ch1[10], ch2[40];
    while (n--)
    {
        scanf("%s%s", ch1, ch2);
//        printf("Execute %s %s\n", ch1, ch2);
        switch (ch1[0])
        {
            case 'i':
                sol.insert(ch2);
                break;
            case 'd':
                sol.remove(ch2);
                break;
            case 's':
                printf(sol.search(ch2) ? "Yes\n" : "No\n");
                break;
        }
//        printf("Current Trie\n");
//        sol.print();
    }
    return 0;
}