#include<fstream>
#include<vector>
#include<cstring>
using namespace std;

struct cell
{
    int frecv;
    bool ok;
    cell *e[30];
    cell()
    {
        ok=0;
        frecv=0;
        for (int i=1;i<=26;i++) e[i]=NULL;
    }
};

ifstream fin("trie.in");
ofstream fout("trie.out");

const int oo=1<<30;

int sol;
char s[30];
cell *root=new cell;

inline void ADAUGA(char *t,cell *p,int i,int len)
{
    if (p->e[t[i]-'a'+1]==NULL) p->e[t[i]-'a'+1]=new cell;
    p->e[t[i]-'a'+1]->frecv=p->e[t[i]-'a'+1]->frecv +1;
    if (i==len) p->e[t[i]-'a'+1]->ok=1;
    if (i<len) ADAUGA(t,p->e[t[i]-'a'+1],i+1,len);
}

inline void STERGE(char *t,cell *p,int i,int len,cell *q)
{
    if (i==len)
        {
            p->frecv=p->frecv-1;
            if (p->frecv==0) {p->ok=0;q->e[t[i]-'a'+1]=NULL;}
            return ;
        }
    STERGE(t,p->e[t[i+1]-'a'+1],i+1,len,p);
    p->frecv=p->frecv-1;
    if (p->frecv==0) q->e[t[i]-'a'+1]=NULL;
}

inline int COUNT(char *t,cell *p,int i,int len)
{
    if (p->e[t[i]-'a'+1]==NULL || (i==len && p->e[t[i]-'a'+1]->ok==0) ) {sol=0;return 0;}
    sol=min(sol,p->e[t[i]-'a'+1]->frecv);
    if (i<len) COUNT(t,p->e[t[i]-'a'+1],i+1,len);
    return sol;
}

inline void PREFIX(char *t,cell *p,int i,int len)
{
    if (i==len+1) fout<<i<<"\n";
    else
    if (p->e[t[i]-'a'+1]==NULL) fout<<i-1<<"\n";
    else PREFIX(t,p->e[t[i]-'a'+1],i+1,len);
}

inline void SOLVE()
{
    int ok;
    while (fin>>ok)
        {
           fin>>(s+1);
           if (!ok) ADAUGA(s,root,1,strlen(s+1));
           if (ok==1) STERGE(s,root->e[s[1]-'a'+1],1,strlen(s+1),root);
           if (ok==2) {sol=oo;fout<<COUNT(s,root,1,strlen(s+1))<<"\n";}
           if (ok==3) PREFIX(s,root,1,strlen(s+1));
        }
}

int main()
{
    SOLVE();
    return 0;
}