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()
x=s.find("AB")
y=s.find("BA",x+2)
i=s.find("BA")
j=s.find("AB",i+2)
if x>-1 and y>-1:
    print("yes")
elif i>-1 and j>-1:
    print("yes")
else:print("no")
	 			  			  		 	  	 	  			 	  	