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()
cd = 0
length = len(word)

for i in range(length - 1):
    if cd == 2:
        break
    
    if word[i:i+2] == "AB": 
        for j in range(i+2, length - 1): 
            if word[j:j+2] == "BA": 
                cd = 2 
                break
    elif word[i:i+2] == "BA":
        for j in range(i+2, length - 1):
            if word[j:j+2] == "AB":
                cd = 2 
                break

if cd == 2:
    print("YES")
else:
    print("NO")
