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.
def check(s):
    if('AB' in s and 'BA' in s):return True
    return False
    
s=input()
if(check(s)):print('YES')
else:print('NO')