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.
s=input()
ab = ba = False
for i in range(1, len(s)-1):
    tab = tba = False
    p1 = s[i-1] + s[i]
    p2 = s[i] + s[i+1] 
    if p1 == 'AB' or p2 == 'AB':
        tab = True 
    if p1 == 'BA' or p2 == 'BA':
        tba = True 
    if tba and tab:
        continue
    if tab :
        ab = True
    elif tba :
        ba = True
    if ab and ba:
        print("YES")
        break
else:
    print("NO")