#include <iostream>
#include <cstring>
#include <fstream>
#define VMAX 105
#define INF 2000000000
using namespace std;
ifstream fin ("trie.in");
ofstream fout ("trie.out");

const int mod = 10;
int numere[2][VMAX];

struct nod {

    int cnt, pre;
    nod * next[26];
};


void initializeaza_nod(nod& a)
{
    a.cnt=0;
    a.pre=0;
    for(int i=0;i<26;i++)
        a.next[i]=NULL;
}


void insereaza(nod * trie, string w, int pos) {
    if(pos == w.size()) {
        trie->cnt++;
        trie->pre++;
    } else {
        if(trie->next[w[pos] - 'a'] == NULL)
        {
            trie->next[w[pos] - 'a'] = new nod();
            initializeaza_nod(*(trie->next[w[pos] - 'a']));
        }
        insereaza(trie->next[w[pos] - 'a'], w, pos + 1);
        trie->pre++;
    }
}


void sterge(nod * trie, string w, int pos)
{
    if(pos==w.size())
    {
        trie->cnt--;
        trie->pre--;
    }
    else
    {
        sterge(trie->next[w[pos]-'a'],w,pos+1);
        trie->pre--;
    }
}


int sol_2(nod * trie, string w, int pos)
{
    if(pos==w.size())
        return trie->cnt;
    else
    {
        return sol_2(trie->next[w[pos] - 'a'] , w , pos+1);
    }
}


int sol_3(nod * trie, string w, int pos)
{
    if(trie->pre==0)
        return pos-1;
    else if(trie->next[w[pos] - 'a'] == NULL)
        return pos;
    else
    {
        return sol_3(trie->next[w[pos] - 'a'], w, pos+1);
    }
}

string s;



int main()
{
    ios_base::sync_with_stdio(0);
    long long int n,m,i,j,k,t,q,nr,ult_nr,pow10_,a,b,minim,maxim,suma,lga,lgb;
    nod tree;
    nod* tre=&tree;
    initializeaza_nod(tree);
    while(fin>>n>>s)
    {
        if(n==0)
            insereaza(tre,s,0);
        else if(n==1)
            sterge(tre,s,0);
        else if(n==2)
        {
            n=sol_2(tre,s,0);
            fout<<n<<'\n';
        }
        else
        {
            fout<<sol_3(tre,s,0)<<'\n';
        }
    }



    return 0;
}