#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

struct trie {
  trie *c[26];
  int nrap, endingHere;

  trie() {
    for(int i = 0; i < 26; i++)
      c[i] = NULL;
    nrap = endingHere = 0;
  }

} *start = new trie;

int op, l;
char cuv[25];

void add_cuv(int dim) {
  trie *cnod = new trie;
  cnod = start;

  for(int i = 0; i < dim; i++) {
    if(cnod->c[cuv[i] - 'a'] == NULL)
      cnod->c[cuv[i] - 'a'] = new trie;
    cnod = cnod->c[cuv[i] - 'a'];
    cnod->nrap++;
  }
  cnod->endingHere++;
}

void delete_cuv(int dim) {
  trie *cnod = new trie;
  cnod = start;

  for(int i = 0; i < dim; i++) {
    cnod = cnod->c[cuv[i] - 'a'];
    cnod->nrap--;
  }
  cnod->endingHere--;
}

void print_ap(int dim) {
  trie *cnod = new trie;
  cnod = start;

  int i = 0;
  while(i < dim && cnod->c[cuv[i] - 'a'] != NULL) {
    cnod = cnod->c[cuv[i] - 'a'];
    i++;
  }

  if(i == dim)
    printf("%d\n", cnod->endingHere);
}

void prefix(int dim) {
  trie *cnod = new trie;
  cnod = start;
  int maxl = 0;

  int i = 0;
  while(i < dim && cnod->c[cuv[i] - 'a'] != NULL) {
    cnod = cnod->c[cuv[i] - 'a'];
    if(cnod->nrap > 0)
      maxl = i + 1;
    i++;
  }

  printf("%d\n", maxl);
}

int main() {
  freopen("trie.in", "r", stdin);
  freopen("trie.out", "w", stdout);
  char c;

  while(!feof(stdin)) {
    scanf("%d ", &op);
    fgets(cuv, 22, stdin);
    l = strlen(cuv);
    cuv[l - 1] = NULL;
    l--;

    if(!feof(stdin))
      if(op == 0)
        add_cuv(l);
      else if(op == 1)
        delete_cuv(l);
      else if(op == 2)
        print_ap(l);
      else if(op == 3)
        prefix(l);
  }

  return 0;
}