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()
pos1=string.find('AB')
pos2=string.find('BA')
if abs(pos1-pos2)>1:
    print('YES')
else:
    substr1=string[:min(pos1,pos2)]
    substr2=string[max(pos1,pos2)+2:]
    if substr1.find('AB')>=0 or substr1.find('BA')>=0 or substr2.find('AB')>=0 or substr2.find('BA')>=0:
        print('YES')
    else:
        print('NO')