#include <iostream>
#include <stdio.h>
#include <stdlib.h>

using namespace std;



typedef struct node {
    int apparitions;
    int totalApparitions;
    struct node *children['z' - 'a' + 2];
} NODE;

NODE *root;

NODE *addApparition(NODE *p, char *s){
    if (p == NULL) {
        p = (NODE *)malloc(sizeof(NODE));
        p->apparitions = 0;
        p->totalApparitions = 0;

        for (int i=0; i< ('z'-'a'+1); i++){
            p->children[i] = NULL;
        }
    }

    p->totalApparitions++;
    //if this is the last character
    if (s[0] == '\0') {
        p->apparitions++;
    } else {
        p->children[s[0]-'a'] = addApparition( p->children[s[0]-'a'], s+1);
    }

    return p;
}


NODE *removeApparition(NODE *p, char *s){

    p->totalApparitions--;
    //if this is the last character
    if (s[0] == '\0') {
        p->apparitions--;
    } else {
        p->children[s[0]-'a'] = removeApparition( p->children[s[0]-'a'], s+1);
    }

    if (p->totalApparitions == 0){
        free(p);
        return NULL;
    }
    else {
        return p;
    }
}

int getNrOfApparitions(NODE *p, char *s){
    if (p == NULL){
        return 0;
    } else {
        if (s[0] == '\0') {
            return p->apparitions;
        } else {
            return getNrOfApparitions(p->children[s[0]-'a'], s+1);
        }
    }
}

int getLongestPrefix(NODE *p, char *s, int currentIndex){

    if (s[0] == '\0' || p == NULL) {
        return 0;
    } else {
        int index = getLongestPrefix(p->children[s[0]-'a'], s+1, currentIndex+1);

        if (index != 0){
            return index;
        } else {
            if ((p->children[s[0]-'a'] == NULL && p->totalApparitions>0) || p->totalApparitions - p->children[s[0]-'a']->totalApparitions != 0){
                return currentIndex;
            } else {
                return 0;
            }
        }

    }
}


void handleInput(int op, char *s){

    int nrOfApparitions, longestPrefix;

    switch(op){
    case 0:
        root = addApparition(root, s);
        break;

    case 1:
        root = removeApparition(root, s);
        break;

    case 2:
         nrOfApparitions = getNrOfApparitions(root, s);
        printf("%d\n", nrOfApparitions);
        break;

    case 3:
        longestPrefix = getLongestPrefix(root, s, 0);
        printf("%d\n", longestPrefix);
        break;
    }
}

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

    int op;
    char s[21];

    while (scanf("%d ", &op) != EOF){

        char c;
        scanf("%c", &c);
        int index = 0;
        while (c <= 'z' && c >= 'a'){
            s[index++] = c;
            scanf("%c", &c);
        }
        s[index] = '\0';

        handleInput(op, s);
    }

    return 0;
}