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#include<stdio.h>
#include<stdlib.h>

typedef struct _Node//doubly-linked lists.
{
    char chr;
    struct _Node *prev;
    struct _Node *next;
}Node;

// Delete the given node, and move its original 
// pointer to the previous node if it exists.
void back(Node **ptrNode)
{
    Node *curNode=*ptrNode;//*******
    if(curNode->prev == NULL) return;// Don't do anything with the dummy head.

    if(curNode->next == NULL)// Deleting the last node of the list.
    {
        (*ptrNode)=curNode->prev;
        (*ptrNode)->next=NULL;
        free(curNode);//*******
    }
    else// Deleting nodes in the middle section of the list.
    {
        curNode->next->prev=curNode->prev;
        curNode->prev->next=curNode->next;
        (*ptrNode) = curNode->prev;//********
        free(curNode);
    }
}

// Insert a node right before the given node, 
// and make its original pointer point to the new node.
void insert(Node **ptrNode,char input)
{
    Node *curNode=*ptrNode;
    Node *newNode=(Node*)malloc(sizeof(Node));
    newNode->chr=input;
    newNode->next=curNode->next;
    newNode->prev=curNode;

    if(curNode->next != NULL)// This won't be run if the new node is on the far right of the list.
        curNode->next->prev=newNode;
    curNode->next=newNode;
    (*ptrNode) = newNode; 
}


// Print all nodes from left to right 
// and delete them along the way.
void print(Node *head)
{
    Node *curNode=head->next;
    while (curNode != NULL)
    {
        printf("%c",curNode->chr);
        Node *temp=curNode;
        curNode=curNode->next;
        free(temp);
    }
    free(head);
    printf("\n");
}


int main()
{
    int T,N;
    scanf("%d\n",&T);
    while (T--)
    {
        Node *head=(Node*)malloc(sizeof(Node));//// The head is a dummy node with no data.
        head->prev=NULL;// It's the only node whose prev points to NULL.
        head->next=NULL;
        Node *curNode=head;// curNode is used as a cursor.

        scanf("%d\n",&N);
        while (N--)
        {
            char input=getchar();
            switch (input)
            {
            case 'L':// Move cursor one node to the left. (prev)
                if(curNode->prev != NULL)
                    curNode=curNode->prev;
                break;
            case 'R':// Move cursor one node to the right. (next)
                if(curNode->next != NULL)
                    curNode=curNode->next;
                break;
            case 'B': // Backspace.
                if(curNode->prev != NULL)
                    back(&curNode);
                break;
            default: // Insert char.
                insert(&curNode,input);
                break;
            }
        }
        print(head);// Print and free all nodes.
    }
    return 0;
}