#include <bits/stdc++.h>

using namespace std;

struct Nod
{
    Nod* fii[26];
    int ap;
    int g;
    Nod()
    {
        for(int i = 0; i < 26; i++)
            fii[i] = NULL;
        ap = 0;
        g = 0;
    }
};

Nod* root = new Nod();

void trieInsert(Nod* root, const char* str)
{
    if (str[0] == '\0')
        root->ap++;
    else
    {
        if (root->fii[str[0] - 'a'] == NULL)
        {
            root->fii[str[0] - 'a'] = new Nod();
            root->g++;
        }
        trieInsert(root->fii[str[0] - 'a'], str + 1);
    }
}

int trieFind(Nod* root, const char* str)
{
    if (str[0] == '\0')
        return root->ap;
    else if (root->fii[str[0] - 'a'] == NULL)
        return 0;
    else
        return trieFind(root->fii[str[0] - 'a'], str + 1);
}

bool trieErase(Nod* root, const char* str)
{
    bool gd = 0;
    if(str[0] == '\0')
        root->ap--;
    else
    {
        gd = trieErase(root->fii[str[0] - 'a'], str + 1);
        if(gd == 1)
            root->fii[str[0] - 'a'] = NULL;
    }
    if(gd)
        root->g--;
    if(root->g == 0 && root->ap == 0)
    {
        delete root;
        root = NULL;
        return 1;
    }
    else
        return 0;
}

int trieMaxPrefix(Nod* root, const char* str, const int lg)
{
    if(root->fii[str[0] - 'a'] == NULL)
        return lg;
    else
        return trieMaxPrefix(root->fii[str[0] - 'a'], str + 1, lg + 1);
}

char lr[102];
int op;
string s;

int main()
{
    ifstream fin ("trie.in");
    ofstream fout ("trie.out");
    while(fin.getline(lr, 102))
    {
        int sz = strlen(lr);
        int op = 0;
        string s = "";
        op = lr[0] - '0';
        for(int i = 2; i < sz; i++)
            s += lr[i];
        if(op == 0)
            trieInsert(root, s.c_str());
        else if(op == 1)
            trieErase(root, s.c_str());
        else if(op == 2)
            fout << trieFind(root, s.c_str()) << "\n";
        else
            fout << trieMaxPrefix(root, s.c_str(), 0) << "\n";
    }
    return 0;
}