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()
p = s.count('AB')
q = s.count('BA')
r = s.count('ABA')
t = s.count('BAB')
n = p+q-r-t
if n >= 2 and p > 0 and q > 0:
    print('YES')
else:
    print('NO')
 		  	 	 		 				 							 			 		