#include<stdio.h>
#include<algorithm>
#include<string.h>
using namespace std;
struct node
{
    node *next[26];
    bool flag;
    int sum[26];
};
node* H;
node* init()
{
    node* tmp = new node;
    for(int i = 0;i < 26;i ++)
    {
        tmp ->sum[i] = 0;
        tmp ->next[i] = NULL;
    }
    tmp ->flag = false;
    return tmp;
}
void del(node* tmp)
{
    for(int i = 0;i < 26;i ++)
    {
        if(tmp ->next[i] != NULL)
            del(tmp ->next[i]);
    }
    free(tmp);    
}
void fun(node *tmp)
{
    //puts("1");
    for(int i = 0;i < 26;i ++)
    {
        tmp ->sum[i] = 0;
        if(tmp ->next[i] != NULL)
            fun(tmp ->next[i]);
        tmp ->next[i] = NULL;
    }
}
void Delete(char *s)
{
    node* tmp = H;
    int len = strlen(s);
    int sum = 0;
    for(int i = 0;i < len;i ++)
    {
        int k = s[i] - 'a';
        if(tmp ->next[k] == NULL)
            return ;
            sum = tmp ->sum[k];
        tmp = tmp ->next[k];
    }
    fun(tmp);
    tmp =H;
    //puts("2");
    for(int i = 0;i < len;i ++)
    {
        int k = s[i] - 'a';
        tmp ->sum[k] -= sum;
        //puts("a");
        tmp =tmp ->next[k];
        //puts("b");
    }
    tmp = H;
    //puts("4");
    for(int i = 0;i < len;i ++)
    {
        int k = s[i] - 'a';
        node* p =tmp;
        tmp =tmp ->next[k];
        if(p ->sum[k] == 0)
            p = NULL;
    }
    //puts("3");
}
bool Search(char *s)
{
    node* tmp = H;
    int len = strlen(s);
    for(int i = 0;i < len;i ++)
    {
        int k = s[i] - 'a';
        if(tmp ->next[k] == NULL||tmp ->sum[k] <= 0)
            return false;
        tmp = tmp ->next[k];
    }
    return true;
}
void Insert(char *s)
{
    node* tmp = H;
    int len = strlen(s);
    for(int i = 0;i < len;i ++)
    {
        int k = s[i] - 'a';
        if(tmp ->next[k] == NULL)
            tmp ->next[k] = init();
        tmp ->sum[k]++;
        tmp = tmp ->next[k];
    }
    tmp ->flag = true;
}
int main()
{
    int N;
    char ss[14000],s[100000];
    while(~scanf("%d", &N))
    {
        H = init();
        while(N--)
        {
            scanf("%s %s",ss,s);
            if(ss[0] == 's')
            {
                bool flag = Search(s);
                //puts("1");
                if(flag)
                    puts("Yes");
                else
                    puts("No");
            }else if(ss[0] == 'i')
            {
                Insert(s);

            }else{
                Delete(s);
            }
        }
        del(H);
    }
    return 0;
}