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

using namespace std;

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

typedef struct trie Trie;

void init (Trie **vertex) {
    (*vertex) = (Trie*) calloc (1,sizeof(Trie));
    /*(*vertex)->words = 0;
    (*vertex)->prefixes = 0;
    memset((void *)&(*vertex)->edges,'\0',sizeof((*vertex)->edges));*/
}

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)
{
    int k;
    if(word.length() != position)
    {
        vertex->prefixes--;
        k = word[position]%26;
        remove (vertex->edges[k], word, ++position);
        if (vertex->edges[k]->prefixes == 0 && vertex->edges[k]->words == 0)
        {
            free(vertex->edges[k]);
            vertex->edges[k] = NULL;
        }
    }
    else
    {
        vertex->words--;
    }
}

void print (Trie* vertex, string word, int position)
{
    if (word.length() == position) 
    {
        printf("%d\n", vertex->words);
    }
    else
    {
        int next_pos = word[position]%26;
        if (vertex->edges[next_pos] != NULL)
        {
            print(vertex->edges[next_pos], word, ++position);
        }
        else
        {
            printf ("0\n");
        }
    }
}

void max_prefix(Trie* vertex, string word, int position)
{
    if (word.length() == position)
    {
        printf("%d\n",position);
    }
    else
    {
        if (vertex->prefixes == 0)
        {
            if (vertex->words == 0)
            {
                printf("%d\n",position - 1);
            }
            else
            {
                printf("%d\n", position);
            }
        }
        else
        {
            int next_pos = word[position] % 26;
            if (vertex->edges[next_pos] != NULL)
            {
                max_prefix (vertex->edges[next_pos], word, ++position);
            }
            else
            {
                printf("%d\n",position);
            }
        }
    }
}


int main() {
    int x;
    char text[21];
    freopen("trie.in", "r", stdin);
    freopen("trie.out","w",stdout);
    Trie* firstVertex;
    init (&firstVertex);
    while (scanf("%d %s\n",&x, text)!= EOF)
    {
       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;
        } 
    }
}