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.
# LUOGU_RID: 101605061
s = input()
u = s.find('AB')
v = s.find('BA')
print('YES' if u != -1 and s.find('BA', u + 2 != -1)
            or v != -1 and s.find('AB', v + 2) != -1 else 'NO')
