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()
a = s.split('AB')
b = s.split('BA')

print("YES") if ((len(a) > 1 and 'BA' in a[1]) or (len(b) > 1 and 'AB' in b[1])) else print("NO")
		   		 		 				 	  		 		   	 		