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.
word = input()
if 'AB' in word:
  AB_index = word.find('AB')
  word = word[:word.find('AB')] + word[word.find('AB')+2:]
  if 'BA' in word:
    print("YES")
  else:
      print("NO")
else:
    print("NO")