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()
flag1 = False
flag2 = False
flag3 = False
if s.find('ABA') != -1:
    flag3 = True
    s = s.replace('ABA', 'C')
if s.find('AB') != -1:
    flag1 = True
if s.find('BA') != -1:
    flag2 = True

if (flag1 and flag2) or (flag1 and flag3) and (flag2 and flag3) or s.find('ABA') >= 2:
    print('YES')
else:
    print('NO')