You are given string *s*. Your task is to determine if the given string *s* contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order).
The only line of input contains a string *s* of length between 1 and 10<sup class="upper-index">5</sup> consisting of uppercase Latin letters.
a=input ()
if "AB" in a and "BA" in a and "BAB" not in a and "ABA" not in a:
  print ("YES")  
elif "ABA" in a or "BAB" in a:
  if a.count("BA")>1 or a.count("AB")>1:
    print ("YES")
  else:
    print("NO")
else:
  print ("NO")