#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cmath>
#include <map>
using namespace std;
int p = 0;
int nt[3000010] , top[3000010] , num[3000010];
char dic[3000010] , mo[10] , ch[35];
void insertt()
{
    int ln = strlen( ch ), fa = 0;
    for( int i=0 ; i<ln ; i++ )
    {
        int nxt = -1;
        for( int j=top[fa] ; j!=-1 ; j=nt[j] )
            if( dic[j] == ch[i] )
            {
                nxt = j; break;
            }
        if( nxt == -1 )
        {
            dic[p] = ch[i];
            nt[p] = top[fa]; top[fa] = p;
            top[p] = -1;
            fa = p++;
        }
        else fa = nxt;
    }
}
int af[35];
void ddell()
{
    int ln = strlen( ch ) , fa = 0;
    for( int i=0 ; i<ln ; i++ )
    {
        int nxt = -1;
        for( int j=top[fa] ; j!=-1 ; j=nt[j] )
            if( dic[j] == ch[i] )
            {
                nxt = j; break;
            }
        if( nxt == -1 ) return ;
        fa = nxt;
        af[i+1] = fa;
    }
    af[0] = 0;
    for( int i=ln-1 ; i>=0 ; i-- )
    {
        fa = af[i];
        if( nt[ top[fa] ] != -1 )
        {
            if( dic[ top[fa] ] == ch[i] ) top[fa] = nt[ top[fa] ];
            else
            {
                for( int j=top[fa] ; j!=-1 ; j=nt[j] )
                    if( nt[j] != -1 && dic[ nt[j] ] == ch[i] )
                    {
                        nt[j] = nt[ nt[j] ];
                        break;
                    }
            }
            return ;
        }
    }
    top[0] = -1;
    return ;
}
bool ssh()
{
    int ln = strlen( ch ) , fa = 0;
    for( int i=0 ; i<ln ; i++ )
    {
        int nxt = -1;
        for( int j=top[fa] ; j!=-1 ; j=nt[j] )
            if( dic[j] == ch[i] )
            {
                nxt = j; break;
            }
        if( nxt == -1 ) return false;
        fa = nxt;
    }
    return true;
}
int main()
{
    int n;
    while( scanf( "%d" , &n ) != EOF )
    {
        p = 1;
        nt[0] = -1;
        top[0] = -1;
        while( n-- )
        {
            scanf( "%s %s" , mo , ch );
            if( mo[0] == 'i' ) insertt();
            else if( mo[0] == 'd' ) ddell();
            else if( mo[0] == 's' )
            {
                if( ssh() ) puts( "Yes" );
                else puts( "No" );
            }
        }
    }
    return 0;
}