#include <cstdio>
#include <cstring>

class Node {
public:
  int freq;
  int sons;
  Node* edges[26];
  
  Node () {
    freq = 0;
    sons = 0;
    for (int i = 0; i < 26; i++) {
      edges[i] = 0;
    }
  }
  
  static void addWord(char *s, int pos, Node* node, int length) {
    if (pos == length) {
      node->freq++;
      return;
    }
    if (node->edges[s[pos] - 'a'] == 0) {
      node->edges[s[pos] - 'a'] = new Node;
      node->sons++;
    }
    addWord(s, pos + 1, node->edges[s[pos] - 'a'], length);
  }
  
  static bool deleteWord(char *s, int pos, Node *node, int length) {
    if (pos == length) {
      node->freq--;
      if (node->freq == 0 && node->sons == 0 && pos != 0) {
        delete node;
        return true;
      } else {
        return false;
      }
    }
    if (deleteWord(s, pos + 1, node->edges[s[pos] - 'a'], length)) {
      node->sons--;
      node->edges[s[pos] - 'a'] = 0;
    }
    if (node->freq == 0 && node->sons == 0 && pos != 0) {
      delete node;
      return true;
    }
    return false;
  }
  
  static int freqWord(char *s, int pos, Node *node, int length) {
    if (pos == length) {
      return node->freq;
    }
    if (node->edges[s[pos] - 'a'] == 0) {
      return 0;
    }
    return freqWord(s, pos + 1, node->edges[s[pos] - 'a'], length);
  }
  
  static int maxPref(char *s, int pos, Node *node, int length) {
    if (pos == length) {
      return pos;
    }
    if (node->edges[s[pos] - 'a'] == 0) {
      return pos;
    }
    return maxPref(s, pos + 1, node->edges[s[pos] - 'a'], length);
  }
};

Node* root = new Node;

int main() {
  freopen("trie.in", "r", stdin);
  freopen("trie.out", "w", stdout);
  
  int type;
  while (scanf("%d", &type) != EOF) {
    getc(stdin);
    char s[25];
    scanf("%s", s);
    if (type == 0) {
      Node::addWord(s, 0, root, (int)strlen(s));
    } else if (type == 1) {
      bool aux;
      aux = Node::deleteWord(s, 0, root, (int)strlen(s));
    } else if (type == 2) {
      printf("%d\n", Node::freqWord(s, 0, root, (int)strlen(s)));
    } else {
      printf("%d\n", Node::maxPref(s, 0, root, (int)strlen(s)));
    }
  }
  return 0;
}