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.
d=str(input())
a=d.find("AB")
n=d.find("BA",a+2)

aa=d.find("BA")
nn=d.find("AB",a+2)

if (a>=0 and n>=0 )or (aa>=0 and nn>=0):
    print("YES")
else:
    print("NO")