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.
# LUOGU_RID: 113620032
def main():
	a=input()
	l=len(a)
	for i in range(l-1):
		s=a[i+1]+a[i]
		if s in a:
			print('YES')
			return
	print('NO')
main()