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.
text = list(input())
length = len(text) 
BA = False
AB = False

index = 1
while index < length :
    if text[index] + text[index - 1] == "BA" : 
        BA = True
        index += 1
    elif text[index] + text[index - 1] == "AB" : 
        AB = True
        index += 1
    index += 1
print("YES" if BA and AB else "NO")