#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<bitset>
using namespace std;

struct trie
{
	int v, p;
	trie *next[26];
	trie()
	{
		v = p = 0;
		for (int i = 0; i < 26; ++i)
			next[i] = 0;
	}
};

trie *t = new trie;

void insert(char* cuv);
void erase(char* cuv);
void writen(char* cuv);
void writep(char* cuv);

int main()
{
	freopen("trie.out", "w", stdout);
	freopen("trie.in", "r", stdin);
	
	char line[32];

	while (!feof(stdin))
	{
		fgets(line, 32, stdin);
		switch (line[0] - '0')
		{
		case 0:
			insert(line + 2); break;
		case 1:
			erase(line + 2); break;
		case 2:
			writen(line + 2); break;
		case 3:
			writep(line + 2); break;
		};
	}
	return 0;
}

void insert(char* cuv)
{
	trie *aux =  new trie;
	aux = t;
	for (int i = 0; i < (int)strlen(cuv) - 1; ++i)
	{
		if (aux->next[cuv[i] - 'a'] == 0)
		{
			trie *nod = new trie;
			aux->next[cuv[i] - 'a'] = nod;
			aux = nod;
		}
		else
		{
			aux = aux->next[cuv[i] - 'a'];
		}
		++aux->p;
	}
	++aux->v;
}

void erase(char* cuv)
{
	trie *aux = new trie;
	aux = t;
	for (int i = 0; i < (int)strlen(cuv) - 1; ++i)
	{
		aux = aux->next[cuv[i] - 'a'];
		--aux->p;
	}
	--aux->v;
}

void writen(char* cuv)
{
	trie *aux = new trie;
	aux = t;
	for (int i = 0; i < (int)strlen(cuv) - 1; ++i)
		if (aux->next[cuv[i] - 'a'] == 0)
		{
			printf("0\n");
			return;
		}
		else
		{
			aux = aux->next[cuv[i] - 'a'];
		}
	printf("%d\n", aux->v);
}

void writep(char* cuv)
{
	trie *aux = new trie;
	aux = t;
	
	int cont = 0, mx = 0;
	for (int i = 0; i < (int)strlen(cuv) - 1; ++i)
	{
		++cont;
		if (aux->next[cuv[i] - 'a'] == 0)
			break;
		else
			aux = aux->next[cuv[i] - 'a'];
		
		if (aux->p > 0)
			mx = cont;
	}
	printf("%d\n", mx);
}