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()
ans = 'NO'
first_AB = s.find('AB')
if first_AB != -1 and 'BA' in s[first_AB+2:]:
    ans = 'YES'
else:
    first_BA = s.find('BA')
    if first_BA != -1 and 'AB' in s[first_BA+2:]:
        ans = 'YES'
print(ans)
