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()
if 'AB' in s and 'BA' in s:
    ind = s.index('AB')
    h = s[ind + 3:]
    if 'BA' in h:
        print('YES')
    else:
        ind = s.index('BA')
        h = s[ind + 3:]
        if 'AB' in h:
            print('YES')
        else:
            print('NO')
else:
    print('NO')