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

ifstream cin("trie.in");
ofstream cout("trie.out");

struct TrieNode
{
    TrieNode *fii[30];
    int aparitii = 0;

    TrieNode()
    {
        for(int i = 0; i < 26; i++)
            this->fii[i] = NULL;
    }
};

int tip;
char s[30];

TrieNode *R = new TrieNode;

bool Gol(TrieNode *Node)
{
    for(int i = 0; i < 26; i++)
        if(Node->fii[i] != NULL)
            return false;
    return true;
}

void Inserare(char s[])
{
    TrieNode *Curent_Node = R;
    int n = strlen(s);

    for(int i = 0; i < n; i++)
    {
        int lit = s[i] - 'a';
        if(Curent_Node->fii[lit] == NULL)
            Curent_Node->fii[lit] = new TrieNode;

        Curent_Node = Curent_Node->fii[lit];
    }

    Curent_Node->aparitii++;
}

TrieNode* Stergere(TrieNode *Curent_Node, int pasi, char s[])
{
    if(Curent_Node == NULL)
        return NULL;

    if(pasi == strlen(s))
    {
        if(Curent_Node->aparitii != 0)
            Curent_Node->aparitii--;

        if(Curent_Node->aparitii == 0 && Gol(Curent_Node))
        {
            delete (Curent_Node);
            return NULL;
        }

        return Curent_Node;
    }

    int lit = s[pasi] - 'a';
    Curent_Node->fii[lit] = Stergere(Curent_Node->fii[lit], pasi + 1, s);

    if(Gol(Curent_Node) && Curent_Node->aparitii == 0)
    {
        delete (Curent_Node);
        return NULL;
    }

    return Curent_Node;
}

int Aparitii(char s[])
{
    TrieNode *Curent_Node = R;
    int n = strlen(s);
    
    for(int i = 0; i < n; i++)
    {
        int lit = s[i] - 'a';
        if(Curent_Node->fii[lit] == NULL)
            return 0;

        Curent_Node = Curent_Node->fii[lit];
    }

    return Curent_Node->aparitii;
}

int Prefix_MAX(char s[])
{
    TrieNode *Curent_Node = R;
    int n = strlen(s);
    
    for(int i = 0; i < n; i++)
    {
        int lit = s[i] - 'a';
        if(Curent_Node->fii[lit] == NULL)
            return i;

        Curent_Node = Curent_Node->fii[lit];
    }

    return n;
}

int main()
{
    while(cin >> tip >> s)
    {
        if(tip == 0)
            Inserare(s);
        else if(tip == 1)
            R = Stergere(R, 0, s);
        else if(tip == 2)
            cout << Aparitii(s) << '\n';
        else
            cout << Prefix_MAX(s) << '\n';
    }

    return 0;
}