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()
a=s.count('AB')
b=s.count('BA')
if a==0 or b==0:
    print('NO')
elif a==1 and b==1 and ('BAB' in s or 'ABA' in s):
    print('NO')
elif a==1 and b==2 and ('BABA' in s):
    print('NO')
elif a==2 and b==1 and ('ABAB' in s):
    print('NO')
else:
    print('YES')