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()
a = s.find('AB')
b = s.find('BA')
if a >= 0 and s.find('BA', a+2) > 0:
    print('YES')
elif b >= 0 and s.find('AB', b+2) > 0:
    print('YES')
else:
    print('NO')