#define IA_PROB "trie"


#include <cstring>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>

#include <algorithm>

#include <fstream>
#include <iostream>

using namespace std;


class Trie {
private:
	const char eow = 'z' + 1;
	struct node {
		int refcnt;
		node* children[27];
		node() : refcnt(0) {
			memset(children, 0, sizeof(children));
		}
	} root;

	void _remove(node *n, string &word, int i) {
		n->refcnt--;
		if (i < word.size()) {
			node *child = n->children[word[i] - 'a'];
			_remove(child, word, i + 1);
			if (child->refcnt == 0) {
				n->children[word[i] - 'a'] = NULL;
				delete child;
			}
		}
	}
public:
	void insert(string &word) {
		node *n = &root;
		n->refcnt++;
		word.push_back(eow);
		for (char c : word) {
			if (n->children[c - 'a'] == NULL) {
				n->children[c - 'a'] = new node();
			}
			n = n->children[c - 'a'];
			n->refcnt++;
		}
	}
	void remove(string &word) {
		node *n = &root;
		n->refcnt--;
		word.push_back(eow);
		/* we're assuming that word is definitely present;
		 * otherwise we'd first have to look it up. */
		_remove(&root, word, 0);
	}
	int count(string &word) {
		node *n = &root;
		word.push_back(eow);
		for (char c : word) {
			if (n->children[c - 'a'] == NULL) {
				return 0;
			}
			n = n->children[c - 'a'];
		}
		return n->refcnt;
	}
	int max_common_prefix_len(string &word) {
		int ret = 0;
		node *n = &root;
		for (char c : word) {
			if (n->children[c - 'a'] == NULL) {
				break;
			}
			n = n->children[c - 'a'];
			ret++;
		}
		return ret;
	}
};

int main()
{
	char line[ 32 ];
	Trie trie;

	freopen( IA_PROB".in", "r", stdin );
	freopen( IA_PROB".out", "w", stdout );

	fgets( line, 32, stdin );

	while( !feof( stdin ) ) {
		string word(line + 2);
		switch( line[0] ) {
			case '0': trie.insert(word); break;
			case '1': trie.remove(word); break;
			case '2': printf( "%d\n", trie.count(word) ); break;
			case '3': printf( "%d\n", trie.max_common_prefix_len(word) ); break;
		}

		fgets( line, 32, stdin );
	}
	return 0;
}