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()
print('YES'
      if ('AB' in s
          and 'BA' in s.replace('AB', '-', 1))
      or ('BA' in s
          and 'AB' in s.replace('BA', '-', 1))
      else 'NO')
