#include <bits/stdc++.h>

using namespace std;

const int kBuffSize = 1 << 13;

struct Trie {
    Trie* son[26];
    int num_words, num;
    
    Trie() {
        memset(son, 0, sizeof son);
        num = 0;
        num_words = 0;
    }
} *root;

template<class T>
void Allocate(T*& x) {
    static char* buff;
    static int pointer = kBuffSize;
    if (pointer + sizeof(T) >= kBuffSize) {
        buff = new char[kBuffSize];
        pointer = 0;
    }
    x = reinterpret_cast<T*>(buff + pointer);
    pointer += sizeof(T);
}

void Insert(const string& word, int sign) {
    Trie* node = root;
    for (auto&& ch : word) {
        node->num += sign;
        if (node->son[ch - 'a'] == nullptr) {
            Allocate(node->son[ch - 'a']);
        }
        node = node->son[ch - 'a'];
    }  
    node->num_words += sign;
    node->num += sign;
}

int Count(const string& word) {
    Trie* node = root;
    for (auto&& ch : word) {
        if (node->son[ch - 'a'] == nullptr) {
            return 0;
        }
        node = node->son[ch - 'a'];
    }  
    return node->num_words;
}

int Lcp(const string& word) {
    Trie* node = root;
    int lcp = -1;
    for (auto&& ch : word) {
        if (node != nullptr and node->num > 0) {
            ++lcp;
        } else {
            break;
        }
        
        node = node->son[ch - 'a'];
    }
    return lcp;
}

int main() {
    ifstream cin("trie.in");
    ofstream cout("trie.out");
    
    int op_type; string word;
    Allocate(root);
    while (cin >> op_type >> word) {
        if (op_type == 0) {
            Insert(word, +1);
        } else if (op_type == 1) {
            Insert(word, -1);    
        } else if (op_type == 2) {
            cout << Count(word) << '\n';
        } else {
            cout << Lcp(word) << '\n';
        }
        
        
    }
    
    return 0;
}