#include <bits/stdc++.h>
#define int long long
#define cin ci
#define cout co
using namespace std;
ifstream cin("trie.in");
ofstream cout("trie.out");
const int nmax = 1e5;
struct Node
{
    int fr, fin;

    int edge[26] = {0};
};
vector<Node> trie;
string s;
int nodes = 1;
void add(int node, int pos)
{
    trie[node].fr ++;
    if(pos == (int)s.size())
    {
        trie[node].fin ++;
        return;
    }

    int next = s[pos] - 'a';

    if(!trie[node].edge[next])
    {
        trie[node].edge[next] = ++ nodes;
        trie.push_back(Node());
    }

    add(trie[node].edge[next], pos + 1);

}
void rem(int node, int pos)
{
    if(node == 0)
        return;
    trie[node].fr --;

    if(pos == (int)s.size())
    {
        trie[node].fin --;
        return;
    }


    int next = s[pos] - 'a';

    rem(trie[node].edge[next], pos + 1);

    if(trie[trie[node].edge[next]].fr == 0)
        trie[node].edge[next] = 0;
}
int maxi = 0;
void query(int node, int pos)
{
    if(node == 0)
        return;
    maxi = max(maxi, pos);

    if(pos < (int)s.size())
    {
        int next = s[pos] - 'a';
        query(trie[node].edge[next], pos + 1);
    }
}
int numaps(int node, int pos)
{
    if(node == 0)
        return 0;

    if(pos == (int)s.size())
        return trie[node].fin;

    int next = s[pos] - 'a';
    return numaps(trie[node].edge[next], pos + 1);
}
int32_t main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    trie.push_back(Node());
    trie.push_back(Node());

    int c;
    while (cin >> c >> s)
    {
        if (c == 0)
            add(1, 0);
        else if (c == 1)
            rem(1, 0);
        else if (c == 2)
            cout << numaps(1, 0) << '\n';
        else
        {
            maxi = 0;
            query(1, 0);
            cout << maxi << '\n';
        }
    }
    return 0;
}