#include<fstream>
#include<vector>
using namespace std;
ifstream fin("trie.in");
ofstream fout("trie.out");

struct node {
	node* nextNode[30] = {};
	long long cuvinteSf = 0;
	long long cuvinteContin = 0;
};

node* root = new node;

/*
adauga un cuvant in arbore
*/
void add(node* currentNode, char* character) {
	currentNode->cuvinteContin++; //cate cuvinte trec prin nodul acesta
	if (character[0] == '\0') { //sfarsitul unui cuvant
		currentNode->cuvinteSf++;
		return;
	}
	int pos = character[0] - 'a';//the next letter
	if (currentNode->nextNode[pos] == nullptr) {
		currentNode->nextNode[pos] = new node;
	}
	add(currentNode->nextNode[pos], character + 1);
}

/*
sterge un cuvant din arbore 
*/
bool remove(node* currentNode, char* character) {
	currentNode->cuvinteContin--;
	if (character[0] == '\0') {
		currentNode->cuvinteSf--;
	}
	else {
		int pos = character[0] - 'a';
		if (remove(currentNode->nextNode[pos], character + 1)) {
			currentNode->nextNode[pos] = nullptr;
		}
	}
	if (currentNode->cuvinteContin == 0 && currentNode != root) {
		delete currentNode;
		return true; //am sters un nod in iteratie
	}
	return false; //nu am sters niciun nod in iteratie
}

/*
tipareste numarul de aparitii ale cuvantului w in lista
*/
int tipareste(node* currentNode, char* character) {
	if (character[0] == '\0') {
		return currentNode->cuvinteSf;
	}
	int pos = character[0] - 'a';
	if (currentNode->nextNode[pos] == nullptr) {
		return 0;
	}
	tipareste(currentNode->nextNode[pos], character + 1);
}

/*
lungimea celui mai lung prefix comun
*/
int prefix(node* currentNode, char* character, int lung) {
	if (character[0] == '\0') {
		return lung; //daca am parcurs cuvantul pana la sfarsit
	}
	int pos = character[0] - 'a';
	if (currentNode->nextNode[pos] == nullptr) {
		return lung; //returnam prima pozitie pentru care nu avem succesori
	}
	if (currentNode->nextNode[pos] != nullptr) {
		prefix(currentNode->nextNode[pos], character + 1, lung + 1);
	}
}

int main() {
	char word[30];
	int op;
	while (fin >> op) {
		fin >> word;
		if (op == 0) {
			add(root, word);
		}
		else if (op == 1) {
			remove(root, word);
		}
		else if (op == 2) {
			fout << tipareste(root, word) << "\n";
		}
		else {
			fout << prefix(root, word, 0) << "\n";
		}
	}
}