#include <iostream>
#include <stdio.h>
#include <string.h>

using namespace std;

const char endCh = '\n';

class Trie {
    Trie* child[26];
    int words, childs;
public:
    Trie() { words = 0; childs = 0; memset(child, 0, sizeof(child));}
    void addWord(char *s);
    bool deleteWord(char *s);
    int countWord(char*);
    int commonPrefix(char*, int);
};

int number(char s){ return s - 'a';}

void Trie::addWord(char *s) {
    if(*s != endCh) {
        if(child[number(*s)] == 0) {
            childs++;
            child[number(*s)] = new Trie;
        }
        child[number(*s)]->addWord(s + 1);
    }
    else words++;
}

bool Trie::deleteWord(char *s) {
    if(*s == endCh) words--;
    else if(child[number(*s)]->deleteWord(s + 1)) {
        delete child[number(*s)];
        child[number(*s)] = 0;
        childs--;
    }

    if(words == 0 && childs == 0) return true;
    return false;
}

int Trie::countWord(char *s) {
    if(*s == endCh) return words;

    if(child[number(*s)] == 0) return 0;

    return child[number(*s)]->countWord(s + 1);
}

int Trie::commonPrefix(char *s, int depth) {
    if(*s == endCh || child[number(*s)] == 0) return depth;

    return child[number(*s)] -> commonPrefix(s + 1, depth + 1);
}

Trie T;

int main() {
    char line[32];

    fgets(line, 32, stdin);
    while(!feof( stdin ) ) {
        switch (line[0]) {
            case '0': T.addWord(line + 2); break;
            case '1': T.deleteWord(line + 2); break;
            case '2': cout << T.countWord(line + 2) << "\n"; break;
            case '3': cout << T.commonPrefix(line + 2, 0) << "\n"; break;
        }
        fgets(line, 32, stdin);
    }
    return 0;
}