import sys
from time import clock
try:
    input=open('in11_6.txt','r')
    output=open('out_26_11_6.txt','w')
except IOError:
    print "The file does not exist"
count=0
for row in input:
    if count==0:
        n=int(row)
    else:
        list=row.split(",")
    count=count+1
    
add=0
count=0
lower=len(list)-1
while(add<=lower):
    
    if(list[add]=='B'):
        while(1):
            if(list[lower]!='B'):
                break
            if(lower==add):
                break
            elif(list[lower]=='B'):
                lower=lower-1
        
        list[add]=list[lower]
        list[lower]='B'
        lower=lower-1
    if(list[add]=='R'):
        while(1):
            
            if(list[count]=='R'and count<lower and count!=add):
                count=count+1
            elif(count==add):
                break
            else:
                break
        list[add]=list[count]
        list[count]='R'
        count=count+1
        
    
    add=add+1
for i in range(0,len(list),1):
    if i==0:
        output.write(str(list[0]))
    else:
        output.write(","+str(list[i]))
input.close()
output.close()