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.count("AB")
b = s.count("BA")
cn = s.count("ABA") + s.count("BAB")
print(["NO", "YES"][(a + b) * (a != 0 and b != 0) - cn > 1])