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.


def main():
    s = input()
    s1 = str(s.split('ABA'))

    if 'AB' in s1 and 'BA' in s1:
        print('YES')
    else:
        print('NO')


main()


