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()
i=0
n=len(s)
count=0
while i<n:
    if s[i]=='A' and i+1<n and s[i+1]=='B':
        count+=1
        i+=1
    elif s[i]=='B' and i+1<n and s[i+1]=='A':
        count+=1
        i+=1
    i+=1
if count>1:print("YES")
else:print('NO')
        