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()
p=0
a=0
b=0
while p<len(s)-1:
    if s[p]+s[p+1]=='AB':
        a+=1
        x=p
    elif s[p]+s[p+1]=='BA':
        b+=1
        y=p
    p+=1
if (a>1 and b>0) or (a>0 and b>1) or (a==1 and b==1 and abs(x-y)!=1):
    print('yes')
else:
    print('no')
    
        
        
        
       

    
    
    
