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 a.count("A")>1 and a.count("B")>1:
  if "ABA" in a and a.count("ABA")>1 or a.count("BA")>1 or a.count("AB")>1:
    print ("YES")
  elif "BAB" in a and a.count("BAB")>1 or a.count("BA")>1 or a.count("AB")>1:
    print ("YES")
  else:
    print ("NO")
else:
  print ("NO")