#include <iostream>
#include <fstream>
#include <string>
using namespace std;

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

struct node
{
    int words=0;
    node* parent=0;
    node* edge[26]={};
}* root=new node;

int numberOfChildren(node* nod)
{
    int nr=0;
    for(int i=0;i<26;i++)
        if(nod->edge[i]!=NULL)
            nr++;
    return nr;
}

void addWord(string &w)
{
    node* crawler=root;
    for(int i=0;i<w.length();i++)
    {
        if(crawler->edge[w[i]-'a']==NULL)
        {
            node* element=new node;
            crawler->edge[w[i]-'a']=element;
            element->parent=crawler;
        }
        crawler=crawler->edge[w[i]-'a'];
    }
    crawler->words++;
}

int checkWord(string &w)
{
    node* crawler=root;
    for(int i=0;i<w.length()&&crawler!=NULL;i++)
        crawler=crawler->edge[w[i]-'a'];
    if(crawler!=NULL)
        return crawler->words;
    else return 0;
}

void deleteWord(string &w)
{
    node* crawler=root;
    for(int i=0;i<w.length();i++)
        crawler=crawler->edge[w[i]-'a'];
    crawler->words--;
    for(int i=w.length()-1;i>=0;i--)
    {
        if(crawler->words>0||numberOfChildren(crawler)>0)
            break;
        node* tmp;
        tmp=crawler;
        crawler=crawler->parent;
        crawler->edge[w[i]-'a']=NULL;
        delete tmp;
    }
}

int longestPrefix(string &w)
{
    node* crawler=root;
    int maxPrefix=0;
    bool ok=1;
    for(int i=0;i<w.length();i++)
    {
        crawler=crawler->edge[w[i]-'a'];
        if(crawler==NULL)
            break;
        //cout<<numberOfChildren(crawler)<<" ";
        if(numberOfChildren(crawler)>0)
            maxPrefix=i+1;
        if(crawler->words>0)
            maxPrefix=i+1;
        //cout<<maxPrefix<<" ";

    }

    return maxPrefix;
}

int main()
{
    string w;
    int command;
    while(1)
    {
        fin>>command>>w;
        if(fin.eof())
            break;
        if(command==0)
            addWord(w);
        if(command==1)
            deleteWord(w);
        if(command==2)
            fout<<checkWord(w)<<"\n";
        if(command==3)
            fout<<longestPrefix(w)<<"\n";
    }
    return 0;
}