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()
pos=string.find('AB')
if pos<0:
    print('NO')
else:
    string=string[:pos]+string[pos+1:]
    if string.find('BA')>=0 and string.find('AB')>=0:
        print('YES')
    elif string.find('BA')!=pos:
        print('YES')
    else:
        print('NO')
        
