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')
ba1 = s.find('BA',ab+2)
ba = s.find('BA')
ab1 = s.find('AB',ba+2)

if (ab != -1 and ba1 != -1) or (ba != -1 and ab1 != -1):
    print("YES")
else:
    print("NO")
