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.
word = input()
dp = [0]* len(word)
for index, letter in enumerate(word):
    if letter == "A":
        if dp[index - 1] == 1:
            dp[index] = 2
        else:
            dp[index] = 1
    elif letter == "B":
        if dp[index - 1] == 1:
            dp[index] = 2
        else:
            dp[index] = 1
print("YES" if dp.count(2) > 1 else "NO")