#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <time.h>
struct node {
    char c;
    struct node *prev,*next,*last_same;
};
struct node *lastup=NULL,*lastlow=NULL;
struct node *list=NULL;
struct node *insert(char k,struct node *lastnode){
    struct node *newnode=NULL;
    newnode=(struct node *)malloc(sizeof(struct node));
    newnode->prev=lastnode;
    newnode->next=NULL;
    if(lastnode){
        lastnode->next=newnode;
    }
    newnode->c=k;
    bool isup=isupper(k);
    if(isup){
        newnode->last_same=lastup;
        lastup=newnode;
    }else{
        newnode->last_same=lastlow;
        lastlow=newnode;
    }
    return newnode;
}
struct node *delect(char k,struct node *lastnode){
    struct node *delekt=isupper(k)?lastup:lastlow;
    if(delekt){
        if(delekt->next&&delekt->prev){
            delekt->next->prev=delekt->prev;
            delekt->prev->next=delekt->next;
            if(delekt==lastup){
                lastup=lastup->last_same;
            }else if(delekt==lastlow){
                lastlow=lastlow->last_same;
            }
        }else if((!delekt->next)&&delekt->prev){
            lastnode=delekt->prev;
            lastnode->next=NULL;
            if(delekt==lastup){
                lastup=lastup->last_same;
            }else if(delekt==lastlow){
                lastlow=lastlow->last_same;
            }
        }else if(delekt->next&&(!delekt->prev)){
            list=list->next;
            list->prev=NULL;
            if(delekt==lastup){
                lastup=NULL;
            }else if(delekt==lastlow){
                lastlow=NULL;
            }
            lastnode=NULL;
        }else{
            list->prev=NULL;
            list->next=NULL;
            list->last_same=NULL;
            list->c=0;
            lastnode=NULL;
        }
        free(delekt);
    }
    return lastnode;
}
void printlist(int k,struct node *lastnode){
    struct node *now=lastnode;
    char *strr=(char *)malloc(k+1);
    strr[k]=0;
    while(now&&k){
        char cur=now->c;
        *(strr+k-1)=cur;
        now=now->prev;
        k--;
    }
    printf("%s\n",strr);
    free(strr);
}
char str[2000001]="";//开5000不停50分
int main(){
    int Q;
    scanf("%d",&Q);
    list=(struct node *)malloc(sizeof(struct node));
    list->prev=NULL;
    list->next=NULL;
    list->last_same=NULL;
    list->c=0;
    struct node *currentpos=list;
    while(scanf("%s",str)!=EOF){
        if(*str=='?'){
            int k;
            scanf("%d",&k);
            printlist(k,currentpos);
        }else{
            int len=strlen(str);
            for(int i=0;i<len;i++){
                char nowchar=*(str+i);
                if(nowchar=='M'||nowchar=='m'){
                    currentpos=delect(nowchar,currentpos);
                }else{
                    currentpos=insert(nowchar,currentpos);
                }
            }
        }
    }
    while(currentpos->prev){
        currentpos=currentpos->prev;
        free(currentpos->next);
    }
    free(currentpos);
    return 0;
}