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()
flag, flag2 = False, False
for i in range(0, len(s) - 1, 2):
    if s[i] + s[i + 1] == 'AB':
        flag = True
    if s[i] + s[i + 1] == 'BA':
        flag2 = True
if flag and flag2:
    print('YES')
else:
    print('NO')