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_index = s.find("AB")
ba_index = s.find("BA")

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