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()
x = s.find('AB')
b = s.find('BA')
print("YES" if (x >=0 and s.find('BA', x+2) >= 0) or (b>=0 and s.find('AB', b+2) >= 0) else "NO")
