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()
s1 = s.find('AB') + 1
s2 = s.find('BA') + 1
s3 = s.find('BA', s1 + 1) + 1
s4 = s.find('AB', s2 + 1) + 1
if (s1 != 0 and s3 != 0) or (s2 != 0 and s4 != 0):
    print('YES')
else:
    print('NO')
#print(s1, s2, s3)
