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()

# Check if "AB" followed by "BA" or "BA" followed by "AB" exists in the string.
if ("AB" in s and "BA" in s[s.index("AB") + 2:]) or ("BA" in s and "AB" in s[s.index("BA") + 2:]):
    print("YES")
else:
    print("NO")
 	  	   	 				 	 	 					   	  	