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