#include <fstream>
#include <cstring>
using namespace std;

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

#define MaxC 21

struct Nod {
    Nod() {
        nr_cuv = nr_sons = 0;
        memset(son, 0, sizeof son);
    }

    int nr_cuv, nr_sons;
    Nod* son[26];

};

Nod* T = new Nod;

char sir[21];

void Insert(Nod* nod, char* s);
bool Delete(Nod* nod, char* s);
int  Count (Nod* nod, char* s);
int  Prefix(Nod* nod, char* s, int k);


int main() {

    while(fin.getline(sir, MaxC )) {

        switch(sir[0]) {

            case '0': Insert(T, sir + 2);                    break;
            case '1': Delete(T, sir + 2);                    break;
            case '2': fout << Count (T, sir + 2) << '\n';    break;
            case '3': fout << Prefix(T, sir + 2, 0) << '\n'; break;

        }

    }

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

int Prefix(Nod *nod, char *s, int k )
{
    if ( *s == '\0' || nod->son[*s - 'a'] == 0 )
        return k;

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

int Count(Nod* nod, char* s ) {

    if ( *s == '\0' )
        return nod->nr_cuv;

    if ( nod->son[*s - 'a'] )
            return Count( nod->son[*s - 'a'], s + 1 );
    return 0;

}

bool Delete(Nod* nod, char* s ) {

    if ( *s == '\0' ) {
        nod->nr_cuv--;
    }
    else {
        if ( Delete(nod->son[*s - 'a'], s + 1) ) {

            nod->son[*s - 'a'] = 0;
            nod->nr_sons--;
        }
    }

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

    return false;

}

void Insert(Nod* nod, char* s ) {

    if ( *s == '\0' ) {
        nod->nr_cuv++;
        return;
    }

    if ( nod->son[*s - 'a'] == 0 ) {

        nod->son[*s - 'a'] = new Nod;
        nod->nr_sons++;
    }

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

}