#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <algorithm>

const int ALPHABET = 26;

struct Node {
    int words = 0;
    int in_words = 0;
    Node* children[ALPHABET] = {nullptr};
};

void insert(Node* root, const std::string& str) {
    Node* curr = root;
    for (char c : str) {
        int idx = c - 'a';
        if (!curr->children[idx]) {
            curr->children[idx] = new Node();
        }
        curr = curr->children[idx];
        curr->in_words++;
    }
    curr->words++;
}

void remove(Node* root, const std::string& str) {
    Node* curr = root;
    for (char c : str) {
        int idx = c - 'a';
        curr = curr->children[idx];
        curr->in_words--;
    }
    curr->words--;
}

int count(Node* root, const std::string& str) {
    Node* curr = root;
    for (char c : str) {
        int idx = c - 'a';
        if (!curr->children[idx]) return 0;
        curr = curr->children[idx];
    }
    return curr->words;
}

int find_max(Node* root, const std::string& str) {
    Node* curr = root;
    int result = 0;
    for (int i = 0; i < str.size(); i++) {
        int idx = str[i] - 'a';
        if (!curr->children[idx] || curr->children[idx]->in_words == 0) break;
        curr = curr->children[idx];
        if (i > 0) result = i + 1;
    }
    return result;
}

int main() {
    std::ifstream input("trie.in");
    std::ofstream output("trie.out");

    Node* root = new Node();
    int op;
    std::string str;

    while (input >> op >> str) {
        if (op == 0) {
            insert(root, str);
        } else if (op == 1) {
            remove(root, str);
        } else if (op == 2) {
            output << count(root, str) << '\n';
        } else {
            output << find_max(root, str) << '\n';
        }
    }

    return 0;
}