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()
n=len(s)
ab=0
ba=0
aba=0
bab=0
i=0
while i < n-1:
	#print(i)
	if s[i]=="A" and s[i+1]=="B":
		if i<n-2 and s[i+2]=="A":
			aba+=1
			i+=1
		else:
			ab+=1
		i+=1
	elif s[i]=="B" and s[i+1]=="A":
		if i<n-2 and s[i+2]=="B":
			bab+=1
			i+=1
		else:
			ba+=1
		i+=1
	i+=1
#print(ab,ba, aba,bab)
if ab+ba==0:
	if (aba>1 or bab>1) or (aba>0 and bab>0):
		print("YES")
	else:
		print("NO")
elif ab==0 or ba==0:
	if aba>0 or bab>0:
		print("YES")
	else:
		print("NO")
else:
	print("YES")