#include <fstream>
#include <stdlib.h>
#include <iostream>
#include <string>

using namespace std;

struct trie {
    int words;
    int prefixes;
    struct trie* edges[26];
};

ifstream in ("trie.in", ifstream::in);
ofstream out("trie.out", ofstream::out);

typedef struct trie Trie;

void init (Trie **vertex) {
    (*vertex) = (Trie*) malloc (sizeof(Trie));
    (*vertex)->words = 0;
    (*vertex)->prefixes = 0;
    for (int i = 0; i < 27; i++) {
        (*vertex)->edges[i] = NULL;
    }
}

void add (Trie** vertex, string word, int position) {
    if (word.length() == position) {
        (*vertex)->words++;
    }
    else 
    {
        (*vertex)->prefixes++;
        int next_pos = word[position] % 26;
        if ((*vertex)->edges[next_pos] == NULL)
        {
            init (&((*vertex)->edges[next_pos]));
        }
        add (&((*vertex)->edges[next_pos]), word, ++position);
    }
}

void remove (Trie** vertex, string word, int position)
{
    char k;
    if(word.length() != position)
    {
        (*vertex)->prefixes--;
        k = word[position];
        remove (&((*vertex)->edges[k%26]), word, ++position);
    }
    else
    {
        (*vertex)->words--;
    }
}

void print (Trie** vertex, string word, int position)
{
    if (word.length() == position) 
    {
        out << (*vertex)->words << endl;
    }
    else
    {
        int next_pos = word.at((size_t)position)%26;
        if ((*vertex)->edges[next_pos] != NULL)
        {
            print(&((*vertex)->edges[next_pos]), word, ++position);
        }
        else
        {
            out << 0 << endl;
        }
    }
}

void max_prefix(Trie** vertex, string word, int position)
{
    if (word.length() == position)
    {
        out << position << endl;
    }
    else
    {
        if ((*vertex)->prefixes == 0)
        {
            if ((*vertex)->words == 0)
            {
                out << position - 1 << endl;
            }
            else
            {
                out << position << endl;
            }
        }
        else
        {
            int next_pos = word[position] % 26;
            if ((*vertex)->edges[next_pos] != NULL)
            {
                max_prefix (&(*vertex)->edges[next_pos], word, ++position);
            }
            else
            {
                out << position << endl;
            }
        }
    }
}


int main() {
    int x;
    string text;
    Trie* firstVertex;
    init (&firstVertex);
    in >> x >> text;
    while (in.eof() == false)
    {
       switch (x) {
            case 0 :
                add(&firstVertex, text, 0);
                break;
            case 1 :
                remove(&firstVertex, text, 0);
                break;
            case 2 :
                print(&firstVertex, text, 0);
                break;
            case 3 :
                max_prefix (&firstVertex, text, 0);
                break;
        }
        in >> x >> text;
    }
}