#include <cstdio>
#include <cstring>
using namespace std;

struct trie {

    trie *next[ 27 ];
    bool terminal;
    int cnt, nrfii;

    trie () {
        cnt = nrfii = 0;
        memset( next, 0, sizeof( next ) );
        terminal = false;
    }

};

void inser ( trie * node, char * s ) {

    if ( *s == 0 ) {
        node -> terminal = true;
        node -> cnt++;
        return ;
    }
    if ( ! node -> next[ *s - 'a' ]  ) {
        node -> next[ *s - 'a' ] = new trie;
        node -> nrfii++;
    }
    return inser( node -> next[ *s - 'a' ], s + 1 );
}

int aparitii ( trie * node, char * s ) {

    if ( ! node ) return 0;
    if ( *s == 0 ) return node -> cnt;

    return aparitii( node -> next[ *s - 'a' ], s + 1 );

}

int prefix ( trie *node, char *s, int k ) {

    if ( *s == 0 || !node -> next[ *s - 'a' ] ) return k;
    return prefix( node -> next[ *s - 'a' ], s + 1, k + 1 );

}

int del ( trie * root, trie * node, char *s ) {

    if ( *s == 0 ) {
        node -> cnt--;
    } else if ( del( root, node -> next[ *s - 'a' ], s + 1 ) ) {
        node -> next[ *s - 'a' ] = 0;
        node -> nrfii--;
    }

    if ( node -> cnt == 0 && node -> nrfii == 0 && node != root ) {
        delete node;
        return 1;
    }

    return 0;

}

int main () {

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

    trie *root = new trie;
    int k;
    char s[ 100 ];

    while (  scanf( "%d%s",&k,s ) != EOF ) {
        if ( k == 0 ) inser ( root, s );
        else if ( k == 1 ) del ( root, root, s );
        else if ( k == 2 )printf( "%d\n", aparitii ( root, s ) );
        else printf( "%d\n", prefix( root, s, 0 ) );
    }

    return 0;

}