#include <bits/stdc++.h>

using namespace std;


struct Node{
    Node *son[26];
    int ap, sum;

    Node()
    {
        for(int i=0; i<26; ++i) son[i] = nullptr;
        ap = 0; sum = 0;
    }

    void insert(string &S, int pos){
        ++sum;
        if(pos == S.size()){
            ++ap;
            return;
        }

        int id = S[pos] - 'a';
        if(son[id] == nullptr) son[id] = new Node();

        son[id] -> insert(S, pos+1);
    }

    void erase(string &S, int pos){
        --sum;
        if(pos == S.size()){
            --ap;
            return;
        }

        int id = S[pos] - 'a';
        son[id] -> erase(S, pos+1);

        if(!son[id]->sum){
            delete son[id];
            son[id] = nullptr;
        }
    }

    int count(string &S, int pos){
        if(pos == S.size()) return ap;

        int id = S[pos] - 'a';
        if(son[id] == nullptr) return 0;
        return son[id] -> count(S, pos+1);
    }

    int longest_prefix(string &S, int pos){
        if(pos == S.size()) return pos;

        int id = S[pos] - 'a';

        if(son[id] == nullptr) return pos;
        return son[id] -> longest_prefix(S, pos+1);
    }
};

class TRIE{
    Node *root;
public:
    void init(){
        root = new Node();
    }

    void insert(string &word){
        root -> insert(word, 0);
    }

    void erase(string &word){
        root -> erase(word, 0);
    }

    int count(string &S){
        return root -> count(S, 0);
    }

    int longest_prefix(string &S){
        return root->longest_prefix(S, 0);
    }


} Trie;

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

    int type;
    string word;

    Trie.init();

    while(fin >> type >> word){
        if(type == 0)
            Trie.insert(word);
        else if(type == 1)
            Trie.erase(word);
        else if(type == 2)
            fout << Trie.count(word) << '\n';
        else fout << Trie.longest_prefix(word) << '\n';
    }

    return 0;
}