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()
b = True
if 'AB' in s and 'BA' in s:
    if (('AB' in s) and (('BA' in s[:s.find('AB')]) or ('BA' in s[s.find('AB')+2:]))) or (('BA' in s) and (('AB' in s[:s.find('BA')]) or ('AB' in s[s.find('BA')+2:]))):
        print("YES")
        b = False
if b : print("NO")