#include <fstream>
#include <string>

using namespace std;

ifstream cin("trie.in");
ofstream cout("trie.out");

class node{
private:
    int cnt, words;
    node *v[26];
public:
    node(){
        cnt = 0;
        words = 0;
        for(auto &it:v)
            it = nullptr;
    }
    void add(const string &s, const int &poz){
        if(poz == s.size()){
            cnt++;
            words++;
            return;
        }
        if(v[s[poz] - 'a'] == nullptr)
            v[s[poz] - 'a'] = new node;
        v[s[poz] - 'a']->add(s, poz + 1);
        words++;
    }
    void del(const string &s, const int &poz){
        if(poz == s.size()){
            cnt--;
            words--;
            return;
        }
        v[s[poz] - 'a']->del(s, poz + 1);
        words--;
    }
    int nr_app(const string &s, const int &poz){
        if(poz == s.size()){
            return cnt;
        }
        if(v[s[poz] - 'a'] == nullptr)
            return 0;
        return v[s[poz] - 'a']->nr_app(s, poz + 1);
    }
    int prefix(const string &s, const int &poz){//cel mai lung prefix al lui s comun cu orice alt cuvant
        if(poz == s.size()) {
            return poz;
        }
        if(v[s[poz] - 'a'] == nullptr) {
            return poz;
        }
        if(words == 0)
            return poz - 1;
        return v[s[poz] - 'a']->prefix(s, poz + 1);
    }
};

node *trie = new node;

int main() {
    char c;
    string s;
    while(cin >> c >> s){
        if(c == '0')
            trie->add(s, 0);
        else if(c == '1')
            trie->del(s, 0);
        else if(c == '2')
            cout << trie->nr_app(s, 0) << '\n';
        else cout << trie->prefix(s, 0) << '\n';
    }
    return 0;
}