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.
q = input()
l = q.find("AB")
r = q.rfind("BA")
if l + 1 < r:
    print("YES")
    exit()
l = q.find("BA")
r = q.rfind("AB")
if l + 1 < r:
    print("YES")
    exit()
print('NO')