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()

first_ab = s.find("AB")

first_ba = s.find("BA")

second_ab = s.rfind("AB")

second_ba = s.rfind("BA")

if (first_ab != -1 and second_ba != -1 and abs(first_ab - second_ba) > 1) or (first_ba != -1 and second_ab != -1 and abs(first_ba - second_ab) > 1):
    print("YES")
else:
    print("NO")
