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.
str1 = input()
if 'AB' in str1 and 'BA' in str1[str1.index('AB')+2:]:
    print("YES")
elif 'BA' in str1 and 'AB' in str1[str1.index('BA')+2:]:
    print("YES")
else:
 	   	    	   	    		      		