#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
#define INF 0x3f3f3f3f
#define eps 1e-8
typedef long long LL;

char s1[10], s2[35];
int a[1000010][26], v[1000010], cur, num, n;

void Insert(char* s)
{
    int len = strlen(s);
    cur = 0;
    for (int i = 0; i < len; i++)
    {
        if (a[cur][s[i]-'a']) cur = a[cur][s[i]-'a'];
        else
        {
            a[cur][s[i]-'a'] = ++num;
            cur = num;
        }
        v[cur]++;
    }
}

void Delete(char* s)
{
    int len = strlen(s), tmp;
    cur = 0;
    for (int i = 0; i < len; i++)
    if (a[cur][s[i]-'a'] == 0)
    {
        cur = -1;
        break;
    }
    else cur = a[cur][s[i]-'a'];
    if (cur != -1)
    {
        for (int i = 0; i < 26; i++)
            a[cur][i] = 0;
        tmp = v[cur];
        cur = 0;
        for (int i = 0; i < len; i++)
        {
            cur = a[cur][s[i]-'a'];
            v[cur] -= tmp;
        }
    }
}

bool Search(char* s)
{
    int len = strlen(s);
    cur = 0;
    for (int i = 0; i < len; i++)
    if (v[a[cur][s[i]-'a']] == 0)
        return 0;
    else cur = a[cur][s[i]-'a'];
    return 1;
}

int main()
{
    scanf("%d", &n);
    memset(a, 0, sizeof(a));
    memset(v, 0, sizeof(v));
    num = 0;
    while (n--)
    {
        scanf("%s%s", s1, s2);
        if (s1[0] == 'i') Insert(s2);
        if (s1[0] == 'd') Delete(s2);
        if (s1[0] == 's')
        {
            if (Search(s2)) printf("Yes\n");
            else printf("No\n");
        }
    }
    return 0;
}