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 = str(input())
tab = s.count("AB")
tba = s.count("BA")
flag = 1 if tab > 0 and tba > 0 and (tab+tba-s.count("ABA")-s.count("BAB") >= 2) else 0
print("YES" if flag else "NO")
   	 				 				  	  	  		  	  		