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 'AB' in s and 'BA' in s: 
    if s.index('AB')+2 != s.index('BA'):
        print("YES")
    else:
        print("NO")
else:
    print("NO")