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.
st = input()
contains_AB = 'AB' in st
contains_BA = 'BA' in st

if (contains_AB and 'BA' in st[st.index('AB')+2:]) or (contains_BA and 'AB' in st[st.index('BA')+2:]):
    print("YES")
else:
    print("NO")

 		   	 		 		 	  	  				 	  	