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 s.find('AB') != -1 and s.find('BA') != -1:
    i = s.find('AB') + 2
    if i < len(s):
        if s[i:].find('BA') != -1:
            print('YES')
            exit()
    i = s.find('BA') + 2
    if i < len(s):
        if s[i:].find('AB') != -1:
            print('YES')
            exit()
print('NO')
