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.
str1=input()
z=[]
c=0
ans="NO"
while c<len(str1):
    m=c
    while m<len(str1):
        l=str1[m:m+2]
        z.append(l)
        m=m+2
    if(("AB"in z) and ("BA" in z)):
        ans="YES"
        break
    z=[]
    c+=1
print(ans)