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()
if s.find('AB')!=-1 and s.find('BA')!=-1 and abs(s.find('AB')-s.find('BA'))>=2 : print("YES")
else : print("NO")