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