#include <cstdio>
#include <string>
#include <list>

using namespace std;

#define TR(C,i) \
	for( typeof(C.begin()) i = C.begin(); i != C.end(); i++ )

list< string > L;

void del( char *s ) {
	string t( s );

	TR( L, it )
		if( *it == t ) {
			L.erase( it );
			break;
		}
}

int que( char *s ) {
	string t( s );
	int cnt = 0;

	TR( L, it )
		if( *it == t )
			cnt++;
	return cnt;
}

int pre( char *s ) {
	string t1( s ), t2;
	int i, l1, l2, res = 0;

	l1 = t1.length() - 1;
	
	TR( L, it ) {
		t2 = *it; l2 = t2.length() - 1;
		for( i = 0; i < l1 && i < l2 && t1[i] == t2[i]; i++ );
		res = res < i ? i : res;
	}

	return res;
}


int main() {
	char line[ 32 ];
	
	freopen( "trie.in", "r", stdin );
	freopen( "trie.out", "w", stdout );

	fgets( line, 32, stdin );
	while( !feof( stdin ) ) {
		switch( line[0] ) {
			case '0': L.push_back( line+2 ); break;
			case '1': del( line+2 ); break;
			case '2': printf( "%d\n", que( line+2 ) ); break;
			case '3': printf( "%d\n", pre( line+2 ) ); break;
		}
		fgets( line, 32, stdin );
	}
	return 0;
}