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()

count = 0
flag = False
ab=False
ba=False
i = 0
while i < len(word):
    if word[i:i+2] == 'AB':
        ab = True
        i = i +2
    elif word[i:i+2] == 'BA':
        ba= True
        i = i +2
    else:
        i +=1
    if ab and ba:
        flag = True
        break
   

if flag == True:
    print("YES")
else:
    print('NO')
