#include <stdio.h>
#include <string>
#include <set>

using namespace std;

#define maxl 30
#define maxn 100010
#define mp make_pair
#define ff first
#define ss second

int N, n;
char cuv[maxl];
int nr[maxn];
set < pair <string, int> > S;

int cmp(string s1, string s2)
{
    int i, l1, l2;
    l1 = s1.size(), l2 = s2.size();

    for (i=0; i<min(l1, l2) && s1[i]==s2[i]; i++);

    return i;
}

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

    int tip, v1, v2;
    set < pair <string, int> > :: iterator I;
    string w = "";
    w += 'z' + 1;

    S.insert( mp(w, 0) );

    while (!feof(stdin))
    {
        scanf("%d %s ", &tip, cuv);

        w = string(cuv);

        if (tip == 0)
        {
            I = S.lower_bound( mp(w, 0));

            if (I -> ff == w) nr[I -> ss]++;
            else {
                     S.insert( mp( w, ++N));
                     nr[N] = 1;
                 }
        }

        if (tip == 1)
        {
            I = S.lower_bound( mp( w, 0));
            nr[I -> ss]--;
            if (nr[I -> ss] == 0) S.erase(I);
        }

        if (tip == 2)
        {
            I = S.lower_bound( mp( w, 0));
            if (I -> ff == w) printf("%d\n", nr[I -> ss]);
            else printf("0\n");
        }

        if (tip == 3)
        {
            v1 = v2 = 0;
            I = S.lower_bound( mp( w, 0));

            v1 = cmp(I->ff, w);

            if (I != S.begin())
            {
                I--;
                v2 = cmp(I->ff, w);
            }

            printf("%d\n", max(v1, v2));
        }
    }

    return 0;
}