#include <fstream>
#include <cstring>

#define Size_Of_Alphabet 26

using namespace std;

ifstream fin ("trie.in");
ofstream fout ("trie.out");

class Trie
{
    public :
        int cnt, nr_sons;
        Trie *son[Size_Of_Alphabet];

        Trie()
        {
            cnt = nr_sons = 0;
            memset(son, NULL, sizeof(son));
        }
};

Trie *T = new Trie;
char Line[32];

void Ins(Trie *nod, char *s)
{
    if (*s == NULL)
    {
        nod->cnt += 1;
        return;
    }

    if (nod->son[*s - 'a'] == NULL)
    {
        nod->son[*s - 'a'] = new Trie;
        nod->nr_sons += 1;
    }

    Ins(nod->son[*s - 'a'], s + 1);
}

bool Del(Trie *nod, char *s)
{
    if (*s == NULL)
    {
        nod->cnt -= 1;
    }
    else if (Del(nod->son[*s - 'a'], s + 1))
    {
        nod->son[*s - 'a'] = NULL;
        nod->nr_sons -= 1;
    }

    if (nod->cnt == 0 && nod->nr_sons == 0 && nod != T)
    {
        delete nod;
        return true;
    }
    return false;
}

int Nr_Aparitii(Trie *nod, char *s)
{
    if (*s == NULL)
    {
        return nod->cnt;
    }

    if (nod->son[*s - 'a'] != NULL)
    {
        return Nr_Aparitii(nod->son[*s - 'a'], s + 1);
    }
    return 0;
}

int Max_Prefix(Trie *nod, char *s, int k)
{
    if (*s == NULL || nod->son[*s - 'a'] == NULL)
    {
        return k;
    }
    return Max_Prefix(nod->son[*s - 'a'], s + 1, k + 1);
}

int main()
{
    while (fin.getline(Line, 30))
    {
        switch(Line[0])
        {
            case '0' :
            {
                Ins(T, Line + 2);
                break;
            }
            case '1' :
            {
                Del(T, Line + 2);
                break;
            }
            case '2' :
            {
                fout << Nr_Aparitii(T, Line + 2) << '\n';
                break;
            }
            case '3' :
            {
                fout << Max_Prefix(T, Line + 2, 0) << '\n';
                break;
            }
        }
    }

    fin.close();
    fout.close();
    return 0;
}