#include <bits/stdc++.h>
using namespace std;
ifstream f("trie.in");
ofstream g("trie.out");
struct trie
{
    int val,nrfii;
    trie* fiu[26];
    trie()
    {
        val=nrfii=0;
        memset(fiu,0,sizeof(fiu));
    }
};
trie* T=new trie();
void trie_push(trie* t,char c[],int k)
{
    if(k==strlen(c))
    {
        t->val++;
        return;
    }
    int x=c[k]-'a';
    if(t->fiu[x]==0)
    {
        t->fiu[x]=new trie();
        t->nrfii++;
    }
    trie_push(t->fiu[x],c,k+1);
}
bool trie_delete(trie* t,char c[],int k)
{
    if(k==strlen(c))
        t->val--;
    else
    {
    int x=c[k]-'a';
    if(trie_delete(t->fiu[x],c,k+1))
    {
        t->nrfii--;
        t->fiu[x]=0;
    }
    }
    if(t->val==0 && t->nrfii==0 && t!=T)
    {
        delete t;
        return 1;
    }
    return 0;
}
void trie_query(trie* t,char c[],int k)
{
    if(k==strlen(c))
    {
        g<<t->val<<'\n';
        return;
    }
    int x=c[k]-'a';
    if(t->fiu[x]==NULL)
    {
        g<<'0'<<'\n';
        return;
    }
    trie_query(t->fiu[x],c,k+1);
}
int M;
void trie_prefix(trie *t,char c[],int k)
{
    if(k==strlen(c))
    {
        g<<k<<'\n';
        return;
    }
    int x=c[k]-'a';
    if(t->fiu[x]==0)
    {
        g<<k<<'\n';
        return;
    }
    trie_prefix(t->fiu[x],c,k+1);
}
int C;
char c[21];
int main()
{
    while(f>>C>>c)
    {
        if(C==0)
            trie_push(T,c,0);
        else
        if(C==1)
            trie_delete(T,c,0);
        else
        if(C==2)
            trie_query(T,c,0);
        else
        {
            M=0;
            trie_prefix(T,c,0);
        }
    }
    return 0;
}