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[a.index('AB')+2:]) or ('BA' in a and 'AB' in a[a.index('BA')+2:]):
    print('YES')
else:
    print('NO')
