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()
a=s.count("AB")
b=s.count("BA")
c=s.count("ABA")
if (a-c>0 and b-c>0) or (a>0 and b-c>0) or (a-c>0 and b>0):
    print("YES")
else :
    print("NO")