#include <bits/stdc++.h>

using namespace std;

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

class TRIE
{
private:
    int frec, cntson;
    TRIE* sons[26];
public:
    TRIE()
    {
        frec = cntson = 0;
        memset(sons, 0, sizeof(sons));
    }

    void ADD(string s, int poz)
    {
        int val = s[poz] - 'a';
        if(!sons[val])
        {
            ++cntson;
            sons[val] = new TRIE;
        }

        if(poz == s.size() - 1)
            ++sons[val]->frec;
        else sons[val]->ADD(s, poz + 1);
    }

    void ERASE(string s, int poz)
    {
        int val = s[poz] - 'a';
        if(poz == s.size() - 1)
            --sons[val]->frec;
        else sons[val]->ERASE(s, poz + 1);
        if(sons[val]->frec == 0 && sons[val]->cntson == 0)
        {
            delete sons[val];
            sons[val] = 0;
            --cntson;
        }
    }
    int APARITII(string s, int poz)
    {
        int val = s[poz] - 'a';
        if(sons[val])
        {
            if(poz == s.size() - 1)
                return sons[val]->frec;
            else return sons[val]->APARITII(s, poz + 1);
        }
        else return 0;
    }

    int LCMPR(string s, int poz){
        int val = s[poz] - 'a';
        if(sons[val] && poz < s.size())
            return sons[val]->LCMPR(s, poz + 1);
        else return poz;
    }
};

TRIE *root = new TRIE;

int main()
{
    int op;
    string s;
    while(fin >> op >> s){
        if(op == 0)
            root->ADD(s, 0);
        else if(op == 1)
            root->ERASE(s, 0);
        else if(op == 2)
            fout << root->APARITII(s, 0) << '\n';
        else fout << root->LCMPR(s, 0) << '\n';
    }
    return 0;
}