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()
n=len(s)
count_ABA=s.count("ABA");count_BAB=s.count("BAB")
count_AB=s.count("AB")
count_BA=s.count("BA")
if (count_ABA!=0 or count_BAB!=0) and ((count_AB>1 and count_BA>=1 ) or (count_AB>=1 and count_BA>1)):print("YES")
elif count_ABA==0 and count_BAB==0 and count_AB>=1 and count_BA>=1:print("YES")
else:print("NO")
