#include <iostream>
#include <fstream>
using namespace std;
class trie
{
    struct node
    {
        int n_sons, n_words;
        node *sons[26];
        node()
        {
            n_sons = n_words = 0;
            for(int i = 0; i < 26; ++i)
                sons[i] = NULL;
        }
    };
    node *root;
    public:
    trie()
    {
        root = new node;
    }
    void true_push(char *str, node *here)
    {
        if(*str == NULL)
        {
            here->n_words++;
            return;
        }
        if(here->sons[*str-97] == NULL)
        {
            here->sons[*str-97] = new node;
            here->n_sons++;
        }
        true_push(str + 1, here->sons[*str-97]);
    }
    void push(char *str)
    {
        true_push(str, root);
    }
    bool true_pop(char *str, node *here)
    {
        if(*str == NULL)
            here->n_words--;
        else if(true_pop(str+1, here->sons[*str-97]))
        {
            here->sons[*str-97] = NULL;
            here->n_sons--;
        }
        if(here->n_words == 0 && here->n_sons == 0 && here!=NULL)
        {
            delete here;
            return true;
        }
        return false;
    }
    void pop(char *str)
    {
        true_pop(str, root);
    }
    int count(char *str)
    {
        node *here = root;
        while(*str)
        {
            if(here->sons[*str - 97] == NULL)
                return 0;
            here = here -> sons[*str - 97];
            ++str;
        }
        return here -> n_words;
    }
    int max_pref(char *str)
    {
        int max = 0;
        node *here = root;
        while(*str)
        {
            if(here -> sons[*str - 97] == NULL)
                return max;
            here = here -> sons[*str - 97];
            ++max;
            ++str;
        }
        return max;
    }
};
trie tr;
int main()
{
    int n;
    char str[21];
    ifstream in("trie.in");
    ofstream out("trie.out");
    while(in >> n >> str)
    {
        switch(n)
        {
            case 0: tr.push(str); break;
            case 1: tr.pop(str); break;
            case 2: out << tr.count(str) << "\n"; break;
            case 3: out << tr.max_pref(str) << "\n"; break;
        }
    }
    in.close();
    out.close();
    return 0;
}