program exp2;

var n,jr,jw,jb:integer; 

ch1:char; 

ch:array[1..20]d char; 

begin

readln(n);

for i:=1 to n do read(ch[i]):

jr:=1;jwz=n;jb:=n;:

while (jr<=jw)do

begin

if(ch[jw]='R') 

then begin

ch1:=Ch[jr];Ch[jr]:=ch[jw];ch[jw]:=ch1:jr:=jr+13

end

else if ch[jw]='W'

then jw:=jw-1

else begin

ch1:=ch[jw];ch[jw]:=ch[jb];ch[jb]:=ch1;jw:=jw-1;jb:=jb-1;

end

end;

for i:=1 to n do write(ch[i]);

writeln;

end.

输入:10

RBRBWWRBBR

输出: