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()
a = s.count("AB")
b = s.count("BA")
c = s.count("ABA")
d = s.count("BAB")
if (a+b)-c-d > 1 and (a != 0 and b != 0):
    print('YES')
else:
    print('NO')