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.
str=input()
s1="AB"
s2="BA"
if str.find(s1)+1==str.find(s2) or str.find(s2)+1==str.find(s1) or str.find(s2)==-1 or str.find(s1)==-1 :
    print("NO")
else:
    print("YES")
	 	 	 	 		 	 		   	 	  					  	