#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream fin("trie.in");
ofstream fout("trie.out");
struct Node {
    int cnt, sonCount;
    Node* sons[26];
    Node() {
        cnt = 0;
        sonCount = 0;
        memset(sons, 0, sizeof(sons));
    }
};
Node* root = new Node;
void adaugaCuvant(char* s, Node *node) {
    char c = *s;
    if (c == '\0') {
        node -> cnt++;
        return;
    }
    int i = c - 'a';
    if (node -> sons[i] == NULL) {
        node -> sons[i] = new Node;
        node -> sonCount++;
    }
    adaugaCuvant(s + 1, node -> sons[i]);
}
bool deleteCuvant(char* s, Node *node) {
    char c = *s;
    if (c == '\0') {
        node -> cnt--;
    }
    else {
        int i = c - 'a';
        if (deleteCuvant(s + 1, node -> sons[i])) {
            node -> sonCount--;
            node -> sons[i] = NULL;
        }
    }
    if (node != root && node -> cnt == 0 && node -> sonCount == 0) {
        delete node;
        return true;
    }
    return false;
}
int getAparitii(char *s, Node *node) {
    char c = *s;
    if (c == '\0') {
        if (strlen(s) == 0) {
            return node -> cnt;
        }
        return 0;
    }
    int i = c - 'a';
    if (node -> sons[i] == NULL) {
        return 0;
    }
    return getAparitii(s + 1, node -> sons[i]);
}
int getLongestPrefix(char *s, Node *node) {
    char c = *s;
    if (node -> cnt == 0 && node -> sonCount == 0) {
        return 0;
    }
    if (c == '\0') {
        return 0;
    }
    int i = c - 'a';
    if (node -> sons[i] == NULL) {
        return 0;
    }
    return getLongestPrefix(s + 1, node -> sons[i]) + 1;
}
int main()
{
    int k;
    char w[21];
    while (fin >> k >> w) {
        if (k == 0) {
            adaugaCuvant(w, root);
        }
        else if (k == 1) {
            deleteCuvant(w, root);
        }
        else if (k == 2) {
            fout << getAparitii(w, root) << "\n";
        }
        else {
            fout << getLongestPrefix(w, root) << "\n";
        }
    }
    return 0;
}