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.
string = input()

if 'ABBA' in string or 'BAAB' in string:
    print('YES')
else:
    flag = False
    
    if 'AB' in string:
        if 'BA' in string[string.index('AB') + 2:]:
            flag = True
    if 'BA' in string:
        if 'AB' in string[string.index('BA') + 2:]:
            flag = True
            
    print(('NO', 'YES')[flag])