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 'AB' in s:
    a1 = s.find('AB')
    if 'BA' in s[0:a1] or 'BA' in s[a1+2:]:
        print('YES')
    else:
        if 'BA' in s:
            a2 = s.find('BA')
            if 'AB' in s[0:a2] or 'AB' in s[a2 + 2:]:
                print('YES')
            else:
                print('NO')
        else:
            print('NO')
else:
    print('NO')