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()
ab = s.find('AB')
ba = s.rfind('BA')

if ab != -1 and ba != -1 and abs(ba - ab ) > 1:
    print("YES")
else:
    print("NO")
