#include <bits/stdc++.h>

using namespace std;
ifstream fin("trie.in");
ofstream fout("trie.out");
struct nod{
    nod *fiu[26];
    int end_of;
    int sons;
    nod()
    {
        memset(fiu,0,sizeof(fiu));
        end_of=0;
        sons=0;
    }
};
nod* root=new nod;
int c;
string word;
void add(nod *parent,int pos)
{
    if(pos==word.size())
    {
        parent->end_of++;
        return;
    }
    if(parent->fiu[word[pos]-'a']==0)
    {
        parent->fiu[word[pos]-'a']=new nod;
        parent->sons++;
    }
    add(parent->fiu[word[pos]-'a'],pos+1);
}
bool pop(nod *parent,int pos)
{
    if(pos==word.size())
        parent->end_of--;
    else
        if(pop(parent->fiu[word[pos]-'a'],pos+1))
        {
            parent->fiu[word[pos]-'a']=0;
            parent->sons--;
        }
    if(parent->end_of==0 && parent->sons==0 && parent!=root)
    {
        delete parent;
        return true;
    }
    return false;
}
int count_words(nod *parent,int pos)
{
    if(pos==word.size())
        return parent->end_of;
    if(parent->fiu[word[pos]-'a']==0)
        return 0;
    return count_words(parent->fiu[word[pos]-'a'],pos+1);
}
int common_prefix(nod *parent,int pos)
{
    if(pos==word.size())
        return pos;
    if(parent->fiu[word[pos]-'a']==0)
        return pos;
    return common_prefix(parent->fiu[word[pos]-'a'],pos+1);
}
int main()
{
    while(fin>>c)
    {
        fin>>word;
        if(c==0)
        {
            add(root,0);
            continue;
        }
        if(c==1)
        {
            pop(root,0);
            continue;
        }
        if(c==2)
        {
            fout<<count_words(root,0)<<"\n";
            continue;
        }
        fout<<common_prefix(root,0)<<"\n";
    }
    return 0;
}