#include <cstdio>
#include <vector>
#include <string>
#include <map>
using namespace std;

#define NMAX 100000

struct Trie
{
    map<char, int> child;
};
//root + 30*NMAX , ~(3e6 + 1) 
//vector<Trie> pool(30*NMAX + 1, Trie());
vector<Trie> pool(1, Trie());
//add one extra char-int pair to parent node when each new node is created.
//~ O(30*(48 + 8)NMax) 3 = pair
//vector<bool> word(30*NMAX + 1, false);
vector<bool> word(1, false);

void rte()
{
    *((int *)0) = 1000;
}

int trie_new()
{
    int res = pool.size();
    pool.push_back(Trie());
    word.push_back(false);
    return res;
}

void trie_insert(int root, const string &s)
{
    int node = root;
    map<char, int>::iterator it;
    for(int i = 0; i < s.size(); i++){
        it = pool[node].child.find(s[i]);
        if(it == pool[node].child.end()){
            //child[s[i]] = trie_new() may not update child[s[i]].
            //workaround
            int nxt = trie_new();
            pool[node].child[s[i]] = nxt; 
            node = nxt; 
        }else{
            node = it->second; 
        }
    }
    word[node] = true;
}

void trie_delete_prefix(int root, const string &s)
{
    int node = root;
    int n = s.size();
    if(n == 0){
        return ;
    }
    map<char, int>::iterator it;
    vector<int> path;
    path.push_back(root);
    for(int i = 0; i < n; i++){
        it = pool[node].child.find(s[i]);
        if(it == pool[node].child.end()){
            return;
        }
        node = it->second;
        path.push_back(node);
    }
    word[node] = false;
    for(int i = n - 1; i >= 0; i--){
        node = path[i + 1];
        int parent = path[i];
        pool[parent].child.erase(s[i]);
        //other child-trees or word with shorten prefix
        if(pool[parent].child.size() || word[parent]){
            break;
        }
    }
}

bool trie_search_prefix(int root, const string &s)
{
    int node = root;
    map<char, int>::iterator it;
    for(int i = 0; i < s.size(); i++){
        it = pool[node].child.find(s[i]);
        if(it == pool[node].child.end()){
            return false;
        }
        node = it->second;
    }
    return true;
}
//6 + 1, 30 + 1
char cmd[10], s[50];
int main(int argc, char **argv)
{
    //pool.size == 1 pool[0] = Trie() word[0] = false
    int root = 0;
    int N;
    //1 1e5
    scanf("%d", &N);
    if((N < 1) || (N > NMAX)){
        rte();
    }
    for(int i = 0; i < N; i++){
        //|s| in 1 30?
        scanf("%s%s", cmd, s);
        switch(cmd[0]){
            case 'i':
                trie_insert(root, s);
                break;
            case 'd':
                trie_delete_prefix(root, s);
                break;
            case 's':
                if(trie_search_prefix(root, s)){
                    puts("Yes");
                }else{
                    puts("No");
                }
                break;
            default:
                rte();
                break;
        }
    }
    return 0;
}