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=str(input())
l=0
res=[0,0]#AB,BA
overlap=False
for r in range(len(s)):
    if r-l<1:continue
    cand=s[l:r+1]
    if cand=="AB":res[0]+=1
    if cand=="BA":res[1]+=1
    if l>0 and (s[l-1]+cand=="ABA" or s[l-1]+cand=="BAB"):
        overlap=True
        break
    l+=1
if overlap:print("NO")
elif res[0]>0 and res[1]>0:print("YES")
else:print("NO")