#include <bits/stdc++.h>

using namespace std;

const int SIGMA = 26;

struct Trie {
    struct Node {
        int edges[SIGMA];
        int cnt;
        int sum;

        Node() {
            cnt = 0;
            sum = 0;
            for ( int i = 0; i < SIGMA; i ++ ) edges[i] = 0;
        }
    };

    Trie(): T(1) {}
    vector <Node> T;

    int createNode() {
        T.resize( T.size() + 1 );
        return T.size() - 1;
    }
    void add( int node, const string& s, int idx ) {
        T[node].sum ++;
        if ( idx == (int)s.size() ) {
            T[node].cnt ++;
        } else {
            if ( T[node].edges[s[idx] - 'a'] == 0 ) {
                T[node].edges[s[idx] - 'a'] = createNode();
            }
            add( T[node].edges[s[idx] - 'a'], s, idx + 1 );
        }
    }
    void del( int node, const string& s, int idx ) {
        T[node].sum --;
        if ( idx == (int)s.size() ) {
            T[node].cnt --;
        } else {
            del( T[node].edges[s[idx] - 'a'], s, idx + 1 );
        }
    }
    int numCnt( int node, const string& s, int idx ) {
        
        if ( idx == (int)s.size() ) {
            return T[node].cnt;
        } else {
            if ( T[node].edges[s[idx] - 'a'] == 0 ) return 0;
            return numCnt( T[node].edges[s[idx] - 'a'], s, idx + 1 );
        }
    }    
    int longestPref( int node, const string& s, int idx ) {
        if ( T[node].sum == 0 ) return idx - 1;
        if ( idx == (int)s.size() ) return idx;
        if ( T[node].edges[s[idx] - 'a'] == 0 ) return idx;
        return longestPref( T[node].edges[s[idx] - 'a'], s, idx + 1 );
    }
};
int main() {
    ifstream fin( "trie.in" );
    ofstream fout( "trie.out" );
    int op, root = 0;
    string s;
    Trie trie;
    while ( fin >> op >> s ) {
        if ( op == 0 ) {
            trie.add( root, s, 0 );
        } else if ( op == 1 ) {
            trie.del( root, s, 0 );
        } else if ( op == 2 ) {
            fout << trie.numCnt( root, s, 0 ) << '\n';
        } else {
            fout << trie.longestPref( root, s, 0 ) << '\n';
        }
    }
    return 0;
}