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.
word = input()
if 'AB' in word and 'BA' in word:
    if word.count('AB')>word.count('BA'):
        print('YES')
    elif word.count('AB')<word.count('BA'):
        print('YES')
    elif word.count('AB') == word.count('BA'):
        if abs(word.find('AB')-word.find('BA'))>=2:
            print("YES")
        else:
            print("NO")
else:
    print("NO")