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()

ab = False
ba = False
j = 0
for i in range(len(s)-1):
	if s[j:j+2] == "AB":
		ab = True
		j+=1
	elif s[j:j+2] == "BA":
		ba = True
		j+=1
	j+=1

if (ab and ba):
	print("YES")
else:
	print("NO")
