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()

sp = [c for c in s]

count = 0

for i in range(len(s) - 1):

    if sp[i] == 'A':

        if sp[i + 1] == 'B':

            count +=1

    if sp[i] == 'B':

        if sp[i + 1] == 'A':

            count +=1

if count < 2: print('NO')
else: print('YES')