#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>

#include <iomanip>

#define vt vector
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define pii pair <int, int>

#define fr first 
#define sc second

using namespace std;

string filename = "trie";
ifstream fin(filename + ".in");
ofstream fout(filename + ".out");

////////////////////////////////////////////////////////////

const int SIGMA = 26;

struct Trie{
    int f, cnt;
    Trie *nxt[SIGMA];

    Trie(){
        f = cnt = 0;
        for(int i = 0; i < SIGMA; i++){
            nxt[i] = NULL;
        }
    }
};

Trie *root = new Trie;

void Insert(Trie *node, string s, int ind){
    node->f++;
    if(ind == sz(s)){
        node->cnt++;
        return;
    }

    if(node->nxt[s[ind] - 'a'] == NULL){
        node->nxt[s[ind] - 'a'] = new Trie;
    }

    Insert(node->nxt[s[ind] - 'a'], s, ind + 1);
}

void Erase(Trie *node, string s, int ind){
    node->f--;
    if(ind == sz(s)){
        node->cnt--;
        return;
    }

    Erase(node->nxt[s[ind] - 'a'], s, ind + 1);

    if(node->nxt[s[ind] - 'a']->f == 0){
        node->nxt[s[ind] - 'a'] = NULL;
    }
}

int Count(Trie *node, string s, int ind){
    if(ind == sz(s)){
        return node->cnt;
    }

    if(node->nxt[s[ind] - 'a'] == NULL){
        return 0;
    }

    return Count(node->nxt[s[ind] - 'a'], s, ind + 1);
}

int LCP(Trie *node, string s, int ind){
    if(ind == sz(s)){
        return sz(s);
    }

    if(node->nxt[s[ind] - 'a'] == NULL){
        return ind;
    }

    return LCP(node->nxt[s[ind] - 'a'], s, ind + 1);
}

void solve(){
    int type;
    string s;

    while(fin >> type >> s){
        if(type == 0){
            Insert(root, s, 0);
        }else if(type == 1){
            Erase(root, s, 0);
        }else if(type == 2){
            fout << Count(root, s, 0) << '\n';
        }else{
            fout << LCP(root, s, 0) << '\n';
        }
    }    
}

int main(){

    int T;
    //fin >> T;

    T = 1;

    while(T--){
        solve();
    }

    return 0;
}