#include <bits/stdc++.h>

using namespace std;

ifstream fin("trie.in");
ofstream fout("trie.out");

const int CMAX = 26;

struct Node {
    int frequency_ending_words;
    int frequency_prefix;
    int children[CMAX];

    Node() {
        frequency_ending_words = frequency_prefix = 0;
        for(int i = 0; i < CMAX; i++) {
            children[i] = -1;
        }
    }
};

struct Trie {
    vector<Node> nodes;
    Trie() {
        nodes.push_back(Node());
    }

    int create_node() {
        int index = nodes.size();
        nodes.push_back(Node());
        return index;
    }

    void insert(string& s) {
        int node = 0;
        nodes[node].frequency_prefix++;
        for(char x : s) {
            if(nodes[node].children[x - 'a'] == -1) {
                nodes[node].children[x - 'a'] = create_node();
            }
            node = nodes[node].children[x - 'a'];
            nodes[node].frequency_prefix++;
        }
        nodes[node].frequency_ending_words++;
    }

    void erase(string& s) {
        int node = 0;
        nodes[node].frequency_prefix--;
        for(char x : s) {
            assert(nodes[node].children[x - 'a'] != -1);
            node = nodes[node].children[x - 'a'];
            nodes[node].frequency_prefix--;
        }
        nodes[node].frequency_ending_words--;   
    }

    int get_frequency(string& s) {
        int node = 0;
        for(char x : s) {
            if(nodes[node].children[x - 'a'] == -1) {
                return 0;
            }
            node = nodes[node].children[x - 'a'];
        }
        return nodes[node].frequency_ending_words;
    }

    int get_longest_common_prefix(string& s) {
        int node = 0;
        int i = 0;
        while(i < (int) s.size() && nodes[node].children[s[i] - 'a'] != -1 && nodes[node].frequency_prefix > 0) {
            node = nodes[node].children[s[i] - 'a'];
            i++;
        }
        return i - (nodes[node].frequency_prefix == 0);
    }
}trie;

int type;
string s;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    while(fin >> type >> s) {
        if(type == 0) {
            trie.insert(s);
        }
        else if(type == 1) {
            trie.erase(s);
        }
        else if(type == 2) {
            fout << trie.get_frequency(s) << '\n';
        }
        else {
            fout << trie.get_longest_common_prefix(s) << '\n';
        }
    }

    return 0;
}