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.
string = input()
check_ab = string.find("AB")
check_ba = string.find("BA")

if (check_ab != -1 and string.find("BA", check_ab + 2) != -1) or (check_ba != -1 and string.find("AB", check_ba + 2) != -1):
    print("YES")
else:
    print("NO")

		 	 	  		 		    			 		   		