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 = str(input())

def foobar(string):
    ab = string.find('AB')
    ba = string.find('BA')
    if ab+1 > ba and ba +1 <ab:
        return 'YES'
    return 'NO'

print(foobar(s))