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()
la, ra, lb, rb = s.find("AB"), s.rfind("AB"), s.find("BA"), s.rfind("BA")
print(["NO", "YES"][ra >= 0 and lb >= 0 and ra - lb >= 2 or rb >= 0 and la >= 0 and rb - la >= 2])

