/**
  *  Worg
  */
#include <cstdio>

FILE *fin = freopen("trie.in", "r", stdin); FILE *fout = freopen("trie.out", "w", stdout);

const int TETA = 26;
const int MAX_LEN = 20 + 5;

struct TrieNode {
  TrieNode *sons[TETA];
  int wordCount;

  TrieNode() {
    this->wordCount = 0;
    for(int i = 0; i < TETA; i++) {
      this->sons[i] = NULL;
    }
  }
};

TrieNode *root = new TrieNode;

void Insert(TrieNode *node, char *word) {
  node->wordCount++;
  if(*word == NULL) return;

  if(node->sons[*word - 'a'] == NULL) {
    node->sons[*word - 'a'] = new TrieNode;
  }
  Insert(node->sons[*word - 'a'], word + 1);
}

void Erase(TrieNode *node, char *word) {
  node->wordCount--;
  if(*word == NULL) return;

  Erase(node->sons[*word - 'a'], word + 1);
}

int CountApparitions(TrieNode *node, char *word) {
  if(*word == NULL) {
    int answer = node->wordCount;
    for(int i = 0; i < TETA; i++) {
      if(node->sons[i] != NULL) {
        answer -= node->sons[i]->wordCount;
      }
    }

    return answer;
  }

  if(node->sons[*word - 'a'] == NULL) {
    return 0;
  }

  return CountApparitions(node->sons[*word - 'a'], word + 1);
}

int MaxCommonLength(TrieNode *node, char *word, int currentLength) {
  if(*word == NULL || node->sons[*word - 'a'] == NULL || node->sons[*word - 'a']->wordCount == 0) {
    return currentLength;
  } else {
    return MaxCommonLength(node->sons[*word - 'a'], word + 1, currentLength + 1);
  }
}

int main() {
  int type;
  char word[MAX_LEN];

  while(scanf("%d%s", &type, word) == 2) {
    if(type == 0) {
      Insert(root, word);
    } else if(type == 1) {
      Erase(root, word);
    } else if(type == 2) {
      printf("%d\n", CountApparitions(root, word));
    } else {
      printf("%d\n", MaxCommonLength(root, word, 0));
    }
  }
  
  return 0;
}