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.
word = input()
ab_pos = word.find('AB')
ba_pos = word.find('BA')
if ab_pos != -1 and ba_pos != -1:
    if word.find('BA', ab_pos + 2) != -1:
        print("YES")
    elif word.find('AB', ba_pos + 2) != -1:
        print('YES')
    else:
        print("NO")
else:
    print('NO')