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.
a = input()
ab = a.find('AB')
s = a[:ab] + a[ab+2:]
ba = s.find('BA')
if ba == -1 or ab == -1:
    print('NO')
else:
    print('YES') 
    