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")
if ab_index != -1:
    ba_index = s.find("BA", ab_index + 2)
    if ba_index != -1:
        print("YES")
        exit()

ba_index = s.find("BA")
if ba_index != -1:
    ab_index = s.find("AB", ba_index + 2)
    if ab_index != -1:
        print("YES")
        exit()

print("NO")
