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();lenn=len(s)
p1=s.count("AB");p2=s.count("BA")
t=s.count("ABA");x=s.count("BAB")
p1-=t+x;p2-=t+x
if p1>0 and p2>0:print("YES")
else:print("NO")