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.
s=input()
if 'AB' in s:
  e=s.index('AB')
  s=s[:e]+'  '+s[e+2:]
  if 'BA' in s:
    print('YES')
    exit()
print('NO')