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()
if 'AB' in s:
    for i in range(s.index('AB') + 2, len(s) - 1):
        if s[i] + s[i + 1] == 'BA':
            print('YES')
            exit()
    print('NO')
elif 'BA' in s:
    for i in range(s.index('BA') + 2, len(s) - 1):
        if s[i] + s[i + 1] == 'AB':
            print('YES')
            exit()
    print('NO')
else:
    print('NO')