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.
a=input()

i=a.index("AB")
j=a.index("BA")

if i>=0 and j>=0 and abs(i-j)>1:
	print("YES")
else:
	print("NO")