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();u=s.find('AB');v=s.find('BA')
print('YES'if(u+1and s.find('BA',u+2)+1)or(v+1and s.find('AB',v+2)+1)else'NO')
		 	     						 	 			  					  	