#include <iostream>
#include<fstream>
#include<string>


using namespace std;
ifstream in("trie.in");
ofstream out("trie.out");



int get_offset(char to_get)
{
    return to_get-'a';
}


class node
{
public:
    char node_character;
    node* child_nodes[26] {nullptr};
    int how_many_here;
    int prefix_of;
    bool does_contain(char node)
    {
        return child_nodes [get_offset(node)]!=nullptr;
    }
    void add_node(char newnode)
    {
        if(child_nodes[get_offset(newnode)]==nullptr)
        {
            node* newp=new node(newnode);
            child_nodes[get_offset(newnode)]=newp;
        }

    }

    node(char nd):node_character(nd)
    {
        how_many_here=0;
        prefix_of=0;
    }

    ~node()
    {

    }
};


class trie
{
public:
    node base_node;
    trie():base_node(' ')
    {

    }
    void add_string( string&to_add)
    {
        node* current_node=&base_node;
        for(int i=0; i<to_add.length(); i++)
        {
            if(!current_node->does_contain(to_add[i]))
            {
                current_node->add_node(to_add[i]);
            }
            current_node->prefix_of++;
            current_node=current_node->child_nodes[get_offset(to_add[i])];
        }
        current_node->how_many_here++;
        current_node->prefix_of++;
    }


    void erase_string( std::string&to_delete)
    {
        node* current_node=&base_node;
        current_node->prefix_of--;
        for(int i=0; i<to_delete.length(); i++)
        {
            current_node=current_node->child_nodes[get_offset(to_delete[i])];
            current_node->prefix_of--;
        }
        current_node->how_many_here--;
    }


    node* get_root( string&prefix)
    {
        node* current_node=&base_node;
        for(int i=0; i<prefix.length(); i++)
        {
            if(!current_node->does_contain(prefix[i]))
            {
                return nullptr;
            }
            current_node=current_node->child_nodes[get_offset(prefix[i])];
        }
        return current_node;

    }


    int get_longest_common_prefix_of_string( string&prefix)
    {
        node* current_node=&base_node;
        int maxx=0;
        for(int i=0; i<prefix.length(); i++)
        {
            if(current_node->does_contain(prefix[i]))
            {
                current_node=current_node->child_nodes[get_offset(prefix[i])];
            }
            else
                return i;

            if(current_node->prefix_of==0)
            {
                return i;
            }
        }
        return prefix.length();
    }
};


int main()
{
    trie test_trie;
    int f;
    string input;
    int a,b;
    while(in>>f>>input)
    {
        switch(f)
        {
        case 0:
        {
            test_trie.add_string(input);
        }
        break;


        case 1:
        {
            test_trie.erase_string(input);
        }
        break;


        case 2:
        {
            node*to_get=test_trie.get_root(input);
            if(to_get!=nullptr)
                out<<to_get->how_many_here<<endl;
            else
                out<<0<<endl;
        }
        break;


        case 3:
            out<<test_trie.get_longest_common_prefix_of_string(input)<<endl;
            break;
        }

    }
    return 0;
}