#include <iostream>
#include <fstream>

struct TrieNode {
    int words = 0;
    int in_words = 0;
};

TrieNode graph[100][26][26];

void dfs(const std::string &str, bool subtract = false, int row = 0, int ptr = 0) {
    if (ptr == str.size()) {
        if (ptr > 0) {
            if (!subtract) graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].words++;
            else graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].words--;

            if (!subtract) graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].in_words++;
            else graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].in_words--;
        }
        return;
    }

    if (ptr > 0) {
        if (!subtract) graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].in_words++;
        else graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].in_words--;
    }

    dfs(str, subtract, row + 1, ptr + 1);
}

int count(const std::string &str, int row = 0, int ptr = 0) {
    if (ptr == str.size()) return graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].words;
    return count(str, row + 1, ptr + 1);
}

int find_max(const std::string &str, int row = 0, int ptr = 0) {
    if (ptr == str.size()) return row;
    if (graph[row][str[ptr - 1] - 'a'][str[ptr] - 'a'].in_words > 0) {
        return find_max(str, row + 1, ptr + 1);
    } else {
        return row;
    }
}

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

    int op;
    std::string str;

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

    return 0;
}