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()
n, m = s.find('AB'), s.find('BA')
ni, mi = s.rfind('AB'), s.rfind('BA')
print('YES' if min(n, m, ni, mi) >= 0 and (abs(n - mi) > 1 or abs(m - ni) > 1) else 'NO')