#include <fstream>
#include <cstring>

using namespace std;

ifstream f("trie.in");
ofstream g("trie.out");

const int NMAX = 21;
const int SIGMAX = (int)('z' - 'a' + 1);

int Q, Type;

char S[NMAX];

struct Node
{
    int val = 0;
    int active_sons = 0;

    Node *Next[SIGMAX];

    Node ()
    {
        val = active_sons = 0;

        for(int i = 0; i <= (int)('z' - 'a'); ++i)
            Next[i] = nullptr;
    }
} *Trie = new Node;

static inline void Update (Node *tree, char *word, int upd_val, int remaining_letters)
{
    if(remaining_letters == 0)
    {
        (tree -> val) += upd_val;

        return;
    }

    int Now = (int)(*word - 'a');

    if((tree -> Next[Now]) == nullptr)
        ++(tree -> active_sons), (tree -> Next[Now]) = new Node;

    Update((tree -> Next[Now]), word + 1, upd_val, remaining_letters - 1);

    if(upd_val == -1)
    {
        Node *Son = (tree -> Next[Now]);

        if((Son -> val) == 0 && (Son -> active_sons) == 0)
            delete(Son), --(tree -> active_sons), (tree -> Next[Now]) = nullptr;
    }

    return;
}

static inline int Query (Node *tree, char *word, int remaining_letters)
{
    if(remaining_letters == 0)
        return (tree -> val);

    int Now = (int)(*word - 'a');

    if((tree -> Next[Now]) == nullptr)
        return 0;

    return Query((tree -> Next[Now]), word + 1, remaining_letters - 1);
}

static inline int LCP (Node *tree, char *word, int curr_level, int remaining_letters)
{
    if(remaining_letters == 0)
        return curr_level;

    int Now = (int)(*word - 'a');

    if((tree -> Next[Now]) == nullptr)
        return curr_level;

    return LCP((tree -> Next[Now]), word + 1, curr_level + 1, remaining_letters - 1);
}

int main()
{
    f.tie(nullptr);

    Trie -> val = 1; /// The Empty Set;

    while(f >> Type >> (S + 1))
    {
        if(Type == 0)
            Update(Trie, S + 1, 1, (int)strlen(S + 1));
        else if(Type == 1)
            Update(Trie, S + 1, -1, (int)strlen(S + 1));
        else if(Type == 2)
            g << Query(Trie, S + 1, (int)strlen(S + 1)) << '\n';
        else
            g << LCP(Trie, S + 1, 0, (int)strlen(S + 1)) << '\n';
    }

    return 0;
}