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.
a = input()
if 'AB' in a and 'BA':
    a1 = a.find('AB')
    a2 = a.rfind('AB')
    b1 = a.find('BA')
    b2 = a.rfind('BA')
    if abs(a1 - b1) > 1 or abs(a1 - b2) > 1 or abs(a2 - b1) > 1 or abs(a2 - b2) > 1:
        print('YES')
    else:
        print('NO')
else:
    print('NO')