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.
c="AB"
d="BA"
a=str(input())
h=a.find(c)
k=a.find(d+2)
if h>=0 and k>=0:
    print("YES")
else:
    print("NO")