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()

AB1, AB2 = S.find("AB"), S.rfind("AB")
BA1, BA2 = S.find("BA"), S.rfind("BA")

print("YES" if AB1 != -1 and BA1 != -1 and (AB1 <= BA2-2 or BA1 <= AB2-2) else "NO")