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())
n=len(s)
l1,l2=[i for i in range(n-1)if s[i:i+2]=="AB"],[i for i in range(n-1)if s[i:i+2]=="BA"]
print("YES" if any(abs(i-j)>=2 for i in l1 for j in l2) else "NO")