#include <bits/stdc++.h>

using namespace std;
#if 1
#define cin fin
#define cout fout
ifstream fin("trie.in");
ofstream fout("trie.out");
#endif // 1
int main()
{
    string s;
    int op;
    map<string, int> m;
    while (cin >> op >> s) {
        if (op == 0) {
            m[s]++;
        }
        else if (op == 1) {
            int v = --m[s];
            if (v == 0)
                m.erase(s);
        }
        else if (op == 2) {
            auto it = m.find(s);
            if (it != m.end()) {
                cout << it->second << "\n";
            }
            else cout << "0\n";
        }
        else if (op == 3) {
            for (int i = s.size(); i > 0; i--) {
                string w = s.substr(0, i);
                auto it = m.lower_bound(w);
                if (it == m.end())
                    continue;
                if (it->first.size() < i)
                    continue;
                if (w == it->first.substr(0, i)) {
                    cout << i << "\n";
                    goto nd;
                }
            }
            cout << 0 << "\n";
        nd: {}
        }
    }
}