//Ilie Dumitru
#include<cstdio>
#include<cstring>

struct trie
{
    int nrc, nrAp;
    trie* next[26];

    trie() {this->nrc=this->nrAp=0; for(int i=0;i<26;++i) this->next[i]=0;}
};

trie* capat;
FILE *f=fopen("trie.in", "r"), *g=fopen("trie.out", "w");

void push(char* text, trie* &t)
{
    if(*text)
    {
        if(t)
        {
            if(!t->next[*text-'a'])
                t->nrc++;
            push(text+1, t->next[*text-'a']);
        }
        else
        {
            t=new trie;
            t->nrc=1;
            push(text+1, t->next[*text-'a']);
        }
    }
    else
    {
        if(t)
            t->nrAp++;
        else
        {
            t=new trie;
            t->nrAp=1;
        }
    }
}

void pop(char* text, trie* &t)
{
    if(*text)
    {
        pop(text+1, t->next[*text-'a']);
        if(!t->next[*text-'a'])
        {
            --t->nrc;
            if(!t->nrc)
                delete t;
        }
    }
    else
    {
        t->nrAp--;
        if(!t->nrAp && !t->nrc)
        {
            delete t;
            t=0;
        }
    }
}

int apart(char* text, trie* &t)
{
    if(*text)
        if(t && t->next[*text-'a'])
            return apart(text+1, t->next[*text-'a']);
    if(t)
        return t->nrAp;
    return 0;
}

int lungMax;

void prefix(char* text, trie* &t, int niv=0)
{
    if(t)
    {
        if(*text)
        {
            if(niv>lungMax)
                lungMax=niv;
            prefix(text+1, t->next[*text-'a'], niv+1);
        }
        else if(niv>lungMax)
            lungMax=niv;
    }
}

void solve(int op, char* cuvant)
{
    int l=strlen(cuvant);
    if(cuvant[l-1]=='\n')
        cuvant[--l]=0;
    switch(op)
    {
    case 0:
        {
            push(cuvant, capat);
            break;
        }
    case 1:
        {
            pop(cuvant, capat);
            break;
        }
    case 2:
        {
            fprintf(g, "%i\n", apart(cuvant, capat));
            break;
        }
    case 3:
        {
            lungMax=0;
            prefix(cuvant, capat);
            fprintf(g, "%i\n", lungMax);
            break;
        }
    }
}

int main()
{
    int op;
    char cuvant[25];
    fscanf(f, "%i %s", &op, cuvant);
    do
    {
        solve(op, cuvant);
        fscanf(f, "%i %s", &op, cuvant);
    }while(!feof(f));
    solve(op, cuvant);
    fclose(stdin);
    fclose(stdout);
    return 0;
}