#include<cstdio>
#include<fstream>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<bitset>
#include<deque>
#include<queue>
#include<set>
#include<map>
#include<cmath>
#include<cstring>
#include<ctime>
#include<cstdlib>
#include<unordered_map>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second

using namespace std;

struct trie
{
    int cnt, was;
    trie *f[26];

    trie()
    {
        cnt = was = 0;
        memset(f, 0, sizeof(f));
    }
};
trie *root = new trie;

int op, n, i, l;
char s[25];

void add()
{
    trie *t = root;
    for(i = 0; i < n; i++)
    {
        l = s[i] - 'a';

        if(!t->f[l])
            t->f[l] = new trie;

        t->f[l]->was++;
        t = t->f[l];
    }
    t->cnt++;
}

void del()
{
    trie *t = root;
    vector<trie*> v;

    v.pb(t);
    for(i = 0; i < n; i++)
    {
        l = s[i] - 'a';

        t->f[l]->was--;
        t = t->f[l];

        v.pb(t);
    }
    t->cnt--;

    i = n - 1;
    while(v.size() > 1)
    {
        t = v.back();
        v.pop_back();

        if(t->was)
            return;

        trie *mlc = v.back();
        mlc->f[s[i--] - 'a'] = NULL;
        delete t;
    }
}

int count()
{
    trie *t = root;
    for(i = 0; i < n; i++)
    {
        l = s[i] - 'a';

        if(!t->f[l])
            return 0;

        t = t->f[l];
    }

    return t->cnt;
}

int prefix()
{
    trie *t = root;
    for(i = 0; i < n; i++)
    {
        l = s[i] - 'a';

        if(!t->f[l])
            return i;

        t = t->f[l];
    }

    return n;
}

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

    while(scanf("%d %s", &op, s) + 1)
    {
        n = strlen(s);

        if(op == 0)
            add();
        else if(op == 1)
            del();
        else if(op == 2)
            printf("%d\n", count());
        else
            printf("%d\n", prefix());
    }

    return 0;
}