#include <iostream>
#include <fstream>
#include <cstring>

struct Node {
    int words = 0;
    int in_words = 0;
    Node* children[26] = {nullptr};
};

Node* root = new Node();

void insert(const std::string& str, int val) {
    Node* node = root;
    for (int i = 0; i < str.size(); i++) {
        int idx = str[i] - 'a';
        if (!node->children[idx]) {
            node->children[idx] = new Node();
        }
        node = node->children[idx];
        node->in_words += val;
    }
    node->words += val;
}

int count(const std::string& str) {
    Node* node = root;
    for (int i = 0; i < str.size(); i++) {
        int idx = str[i] - 'a';
        if (!node->children[idx]) return 0;
        node = node->children[idx];
    }
    return node->words;
}

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

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

    int op;
    std::string str;

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

    return 0;
}