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()

c = 0

i = 0

while i < (len(s) - 1): 

    l = s[i]
    
    if l == 'B':

        if s[i + 1] == 'A': 
            
            c+=1
            i += 2

    elif l == 'A':

        if s[i + 1] == 'B': 
            
            c +=1
            i += 2

    else: i += 1

if c > 1: print('YES')
else: print('NO')