#include <fstream>
#include <cstring>
#include <cstdlib>
#define lmax 25

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

struct tnode
{
    tnode *ch[26];
    int words;
    bool leaf;
    int app;
    tnode()
    {
        this->leaf = false;
        this->app = 0;
        this->words = 0;
        memset(this->ch, 0, sizeof(this->ch));
    }
};
tnode *trie;
char s[lmax], *p;
int qtype;

int maxx(int a, int b)
{
    if (a>b)
    {
        return a;
    }
    return b;
}

bool existsInTrie(tnode *t, char *s)
{
    if (!(*s))
    {
        return t->leaf;
    }
    if (!t->ch[*s-'a'])
    {
        return false;
    }
    return existsInTrie(t->ch[*s-'a'],s+1);
}

void insertInTrie(tnode *t, char *s, bool exists)
{
    if (!(*s))
    {
        if (!exists)
        {
            t->leaf = true;
            t->app = 1;
            ++t->words;
        }
        else
        {
            ++t->app;
        }
        return;
    }
    if (!t->ch[*s-'a'])
    {
        t->ch[*s-'a'] = new tnode();
    }
    if (!exists)
    {
        ++t->words;
    }
    insertInTrie(t->ch[*s-'a'], s+1, exists);
}

int cntApTrie(tnode *t, char *s)
{
    if (!(*s))
    {
        return t->app;
    }
    return cntApTrie(t->ch[*s-'a'], s+1);
}

int largestPreff(tnode *t, char *s, int lg)
{
    if (!(*s))
    {
        if (t->leaf)
        {
            return lg;
        }
        return 0;
    }
    if (!t->ch[*s-'a'])
    {
        return lg;
    }
    int v = largestPreff(t->ch[*s-'a'], s+1, lg+1);
    v = maxx(v, lg);
    return v;
}

bool deleteFromTrie(tnode *t, char *s)
{
    if (!(*s))
    {
        --t->app;
        if (!t->app)
        {
            t->leaf = false;
            --t->words;
        }
        if (!t->words)
        {
            return true;
        }
        return false;
    }
    bool wasD = deleteFromTrie(t->ch[*s-'a'], s+1);
    if (wasD)
    {
        delete t->ch[*s-'a'];
        t->ch[*s-'a'] = NULL;
        --t->words;
    }
    if (!t->words)
    {
        return true;
    }
    return false;
}

int main()
{
    trie = new tnode();
    while (fin.getline(s, lmax))
    {
        p = strtok(s, " ");
        qtype = atoi(p);
        p = strtok(NULL, " ");
        bool ex = existsInTrie(trie, p);
        if (qtype == 0)
        {
            insertInTrie(trie, p, ex);
            //fout<<"Numar aparitii: "<<p<<" : "<<cntApTrie(trie, p)<<'\n';
        }
        else if (qtype == 1)
        {
            if (!ex)
            {
                continue;
            }
            deleteFromTrie(trie, p);
        }
        else if (qtype == 2)
        {
            if (!ex)
            {
                fout<<0<<'\n';
                continue;
            }
            fout<<cntApTrie(trie, p)<<'\n';
        }
        else
        {
            fout<<largestPreff(trie, p, 0)<<'\n';
        }
    }
    fin.close();
    fout.close();
    return 0;
}