#include <iostream>
#include <fstream>

#define CH(s) s-'a'

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

struct Trie
{
    int cnt, nrfii;
    Trie* fiu[26];
};
Trie* T = new Trie();

void insereaza(Trie* nod, char* s)
{
    if (*s == 0)
    {
        nod->cnt++;
        return;
    }
    if (nod->fiu[CH(*s)] == NULL)
    {
        nod->fiu[CH(*s)] = new Trie();
        nod->nrfii++;
    }
    insereaza(nod->fiu[CH(*s)], s + 1);
}

int sterge(Trie* nod, char* s)
{
    if (*s == 0)
    {
        nod->cnt--;
    }
    else if (sterge(nod->fiu[CH(*s)], s + 1))
    {
        nod->fiu[CH(*s)] = NULL;
        nod->nrfii--;
    }
    if (nod->cnt == 0 && nod->nrfii == 0 && nod != T)
    {
        delete nod;
        return 1;
    }
    return 0;
}

int aparitii(Trie* nod, char* s)
{
    if (*s == 0)
        return nod->cnt;
    if (nod->fiu[CH(*s)])return aparitii(nod->fiu[CH(*s)], s + 1);
    return 0;
}

int lungmax(Trie* nod, char* s, int k)
{
    if (*s == 0 || nod->fiu[CH(*s)] == NULL)
        return k;
    else return lungmax(nod->fiu[CH(*s)], s + 1, k + 1);
}

int main()
{
    char line[32];
    fin.getline(line, 32);
    while (!fin.eof())
    {
        switch (line[0])
        {
        case '0': insereaza(T, line + 2); break;
        case '1': sterge(T, line + 2); break;
        case '2': fout << aparitii(T, line + 2) << '\n'; break;
        case '3': fout << lungmax(T, line + 2, 0) << '\n'; break;
        }
        fin.getline(line, 32);
    }
}