#include <stdio.h>
#include <limits.h>
#include <string.h>
#include <assert.h>
#include <stdbool.h>
#include <stdlib.h>

typedef struct Trie
{
    int count;
    int appearances;
    struct Trie* letters[26];

} TRIE, *PTRIE;

void
addWordToTrie(PTRIE trie,
              char* word)
{
    if (NULL == trie)
    {
        return;
    }

    if (NULL == word)
    {
        return;
    }

    ++(trie -> count);
    if ('\n' == *word)
    {
        ++(trie -> appearances);
        return;
    }

    if (NULL == (trie -> letters)[*word - 'a'])
    {
        (trie -> letters)[*word - 'a'] = (PTRIE)malloc(sizeof(TRIE));
        if (NULL == (trie -> letters)[*word - 'a'])
        {
            printf("Malloc failed!!\n");
            exit(1);
        }
    }

    addWordToTrie( (trie -> letters)[*word - 'a'],
                   (word + 1) );
}

/* ----------------------------------------------------------------------- */

_Bool
wordExistsInTrie(PTRIE trie,
                 char* word)
{
    if (NULL == trie)
    {
        return false;
    }

    if (NULL == word)
    {
        return false;
    }

    if ('\n' == *word)
    {
        return true;
    }

    if (NULL != (trie -> letters)[*word - 'a'])
    {
        return wordExistsInTrie((trie -> letters)[*word - 'a'],
                                (word + 1));
    }
    else
    {
        return false;
    }
}

/* ----------------------------------------------------------------------- */

void
removeWordFromTrie(PTRIE trie,
                   char* word)
{
    if (NULL == trie)
    {
        return;
    }

    if (NULL == word)
    {
        return;
    }
    
    --(trie -> count);
    if ('\n' == *word)
    {
        --(trie -> appearances);
        return;
    }

    removeWordFromTrie( (trie -> letters)[*word - 'a'],
                        (word + 1) );


    if (0 == (trie -> letters)[*word - 'a'] -> count)
    {
        free((trie -> letters)[*word - 'a']);
        (trie -> letters)[*word - 'a'] = NULL;
    }
}

/* ----------------------------------------------------------------------- */

int
getNumberOccurrences(PTRIE trie,
                     char* word)
{
    if (NULL == trie)
    {
        return 0;
    }

    if ('\n' == *word)
    {
        return trie -> appearances;
    }

    return getNumberOccurrences( (trie -> letters)[*word - 'a'],
                                 (word + 1) );
}

/* ----------------------------------------------------------------------- */

int
getLengthOfLongestCommonPrefix(PTRIE trie,
                               char* word)
{
    if (NULL == trie)
    {
        return 0;
    }

    if ( (NULL == word) ||
         ('\n' == *word) )
    {
        return 0;
    }

    if (NULL != (trie -> letters)[*word - 'a'])
    {
        return (1 + getLengthOfLongestCommonPrefix( (trie -> letters)[*word - 'a'],
                                                    (word + 1) ));
    }
    else
    {
        return 0;
    }
}

/* ----------------------------------------------------------------------- */

int main()
{
    char w[50];
    TRIE* trie;

    trie = (PTRIE)malloc(sizeof(TRIE));
    for (int i = 0; i < 26; ++i)
    {
        (trie -> letters)[i] = NULL;
    }

    freopen("trie.in", "r", stdin);
    freopen("trie.out", "w", stdout);

    fgets(w, 50, stdin);

    while (!feof(stdin) )
    {
        if ('0' == *w)
        {
            addWordToTrie(trie, w + 2);
        }
        else if ('1' == *w)
        {
            removeWordFromTrie(trie, w + 2);
        }
        else if ('2' == *w)
        {
            printf("%d\n", getNumberOccurrences(trie, w + 2));
        }
        else
        {
            printf("%d\n", getLengthOfLongestCommonPrefix(trie, w + 2));
        }

        fgets(w, 50, stdin);
    }

    return 0;
}