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=str(input());a=s.count("AB");b=s.count("BA");c=s.count("ABA");d=s.count("BAB")
if (a!=0 and b!=0) and a+b-c-d>1:print("YES")
else:print("NO")