#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<map>
#define maxn 100010
using namespace std;
int n, q, tot, cnt[maxn * 30];
map<int, int> ch[maxn * 30];
char opt[40], s[40];
void ins()
{
    int x = 0;
    for (int i = 1; i <= n; ++ i){
        if (! ch[x][s[i] - 'a'])
            ch[x][s[i] - 'a'] = ++ tot;
        x = ch[x][s[i] - 'a'];
        ++ cnt[x];
    }
}
void del()
{
    int x = 0;
    for (int i = 1; i <= n; ++ i){
        if (! ch[x][s[i] - 'a']) return;
        x = ch[x][s[i] - 'a'];
    }
    int d = cnt[x]; ch[x].clear(); 
    x = 0;
    for (int i = 1; i <= n; ++ i){
        x = ch[x][s[i] - 'a'];
        cnt[x] -= d;
    }
}
bool exist()
{
    int x = 0;
    for (int i = 1; i <= n; ++ i){
        if (! ch[x][s[i] - 'a']) return 0;
        x = ch[x][s[i] - 'a'];
    }return cnt[x] > 0;
}
int main()
{
    scanf("%d", &q);
    while (q --){
        scanf("%s%s", opt + 1, s + 1);
        n = strlen(s + 1);
        if (opt[1] == 'i') ins();
        if (opt[1] == 'd') del();
        if (opt[1] == 's') puts(exist() ? "Yes" : "No");
    }
    return 0;
}