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.
string=input()
a=string.find('AB')
b=string.find('BA',a+2)
c=string.find('BA')
d=string.find('AB',c+2)
if((a!=-1 and b!=-1) or (c!=-1 and d!=-1)):
    print('YES')
else:
    print('NO')
