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()
ba = s.rfind('BA')
ab = s.find('AB') 

if ab >= 0 and ba >= 0 and abs(ab-ba) > 1:
	print('YES')
else:
	print('NO') 
